Cloud Hosting FAQ

Single Sign-on (SSO) FAQ

What does it mean that ElasticHosts has joined with GoDaddy?
Our joining with GoDaddy means that you will have an even larger product range to choose from, thanks to the use of Single-Sign-On (SSO). The extra resources that come with this merger will also enable us to provide you with even better customer service.

What is SSO?
SSO stands for Single-Sign-On and this allows you to access both your GoDaddy and ElasticHosts accounts with a single login. You can use your ElasticHosts products and services from your ElasticHosts account, but when you need to purchase and use a GoDaddy product or service, you can do so without having to log in again.

Why do I need to connect my ElasticHosts account with a GoDaddy account?
We are beginning the process of migrating your products and services to GoDaddy. If they are linked now, it will make for a seamless transition and easier processing in the future.

Do I need to connect my accounts?
You don’t need to – you can continue to use your ElasticHosts account separate from a GoDaddy account. However, we do recommend connecting your accounts to streamline the process of using them and the products and services within each of them once the GoDaddy migration is complete.

How do I connect my accounts?
All you need to do is log in to your ElasticHosts account and follow the instructions provided.

What happens if I do not connect my ElasticHosts account with a GoDaddy account?
You will still be able to use your ElasticHosts account as you have been doing. However, ElasticHosts will soon be migrated to GoDaddy and you will need a GoDaddy account to access your services. Connecting the accounts now will make it quicker and easier to access your products and services in the future.

When do I need to connect my accounts by?
At the moment, we do not have finalised information and therefore cannot provide an exact date. We will keep you posted on the developments and apologise that we can’t say much more right now.

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Getting Started


####Trial

What does your Free 5-Day Trial include?

The free trial gives you full access to our system and includes 2000 core-MHz CPU, 1024 MB RAM, 30GB HDD, 5GB high performance SSD and 10GB data transfer, which is enough capacity to run a medium-sized server or several small servers.

Are there any restrictions on your Free 5-Day Trial?

  • The free trial is limited to 2000 core-MHz CPU, 1024 MB RAM, 30GB HDD, 5GB high-speed SSD and 10GB data transfer. It lasts for 5 days.
  • During the trial, we block outbound connections to smtp, ftp, ssh and telnet servers – ports FTP (tcp 21), SSH (tcp 22), telnet (tcp 23), SMTP (tcp 25), POP3 (tcp 110), IMAP (tcp 143), SIP (udp 5060), VNC (tcp 5900-2) and Runescape (tcp 43594-5) – to prevent abuse of our trials for sending spam or conducting dictionary attacks against other internet hosts.
  • We ask triallists not to run Minecraft or other game servers. Game servers may be powered off without warning.

Is it possible to have a trial for longer or with extra infrastructure capacity?

We are happy to consider requests for larger and/or longer trials on a case-by-case basis. Please email support@elastichosts.com if you would like extra time or resources.

How do I run Windows during my trial?

There are 3 options for setting up a server to run Windows during your trial:

  1. Use one of our pre-installed Windows images. However, please be aware that these require a licence from Microsoft, and you will have to purchase the correct Windows licence from us if you wish to continue using this after the trial has expired.
  2. Select ‘self-install from CD’, rather than ‘pre-installed images’, and then install from the appropriate trial CD (Windows Server 2008 R2 Trial CD, Windows Web Server 2008 CD or Windows Server 2012 R2 Trial CD) yourself.
  3. Upload your own install CD using our cloud hosting upload tool or SFTP to ftp.<zone>.elastichosts.com (e.g. ftp.lon-p.elastichosts.com) with your account UUID (as username) and Secret API key (as password) as shown on your account profile page.

When I sign up, can I continue to use the servers I created during the trial?

Yes. You can purchase monthly plans or add burst balance at any time from inside your account. If you sign up before the end of your trial, you will be able to continue running your servers uninterrupted.


####Uploading CD/server images

How can I upload my own ISO CD images?

You are welcome to provide your own ISO CD images to use on your servers. You can upload these in one of three ways:

  1. using our API with the ElasticHosts-upload script;
  2. by SFTP (Secure FTP) protocol to ftp.<zone>.elastichosts.com (e.g. ftp.lon-p.elastichosts.com) with your account UUID and Secret API key as shown on your account profile page. We recommend use of the WinSCP application to do this – Filezilla is known not to work; or
  3. if the image is less than 1GB, using the upload web form found on an existing drive's ‘Configure drive’ page. ![Upload image on the control panel](/blog/content/images/2016/05/FAQ-upload-image.png)

How can I upload my own server images?

You can use any of the methods mentioned in the previous question to upload a server image to your account. Using our API upload tool is likely to be the best choice if the image is large, as this uploads in chunks and has the option of resuming an interrupted upload. We can also accept USB hard drives with drive images on, to copy across directly. Please submit a ticket on the control panel or email support@elastichosts.com if you would like further details.

What format server images do you support?

We accept only raw drive images that are the same as a physical drive, with block device, partition tables etc. However, we do accept converted VMware images – see the Converting OS images section below for details.

I have uploaded an ISO9660 image (.iso file). How do I boot a server from it?

On the server configuration page, set the drive media type for the drive containing the image to CD-ROM and ensure the boot radio button is activated next to it. If you are installing a server from the CD, remember you will also need another drive attached onto which to install your operating system.

How can I migrate Linux KVM or QEMU virtual machines into your cloud?

If your drive is already in the raw format supported by these hypervisors, it is ready to upload using our API upload tool unchanged, as described above.

If your drive is in qcow2 format, you will need to convert it to raw format before uploading. You can do this with the command:

qemu-img convert -f qcow2 -O raw drive.qcow2 drive.raw
where `drive.qcow2` is the qcow2 file you want to convert to the raw file drive.raw.

How can I migrate physical servers into your cloud?

If you have physical servers that you would like to migrate into our cloud, you should boot your server from a live CD and then run the ElasticHosts-upload script to upload the hard disk block device.
However, please note that uploading a large drive this way can take a very long time depending on your internet connectivity. It may be quicker to install afresh in our cloud and copy your data across.

Can I send you data on a physical disk to copy into my account?

Yes.


####Converting server images

I use Hyper-V. Is it possible to upload Hyper-V disk images and use them on the ElasticHosts system?

Yes, although they must be converted first: our system requires either DVD or CD images in .iso format, or raw disk images. Microsoft’s VHD file format can be converted to raw format using qemu-tools:

qemu-img convert -f vpc inputfilename.vhd -O raw outputfilename.raw
If they are installed, it’s important to remove Microsoft’s Virtual Machine Additions before converting, as these non-standard drivers can cause problems on our system.

I use VMWare. Is it possible to upload VMware disk images and use them on the ElasticHosts system?

Only indirectly. Our system requires either DVD or CD images in .iso format, or raw disk images – the equivalent of taking the stream of bytes off a physical disk and saving them in a file. A .vmdk file is a long way from raw format. However, qemu does have tools to convert these.

On a Linux system, you can use the following command to convert a .vmdk into a raw disk image that our system can use:

$ qemu-img convert inputfilename.vmdk -O raw outputfilename.raw
Be aware that a raw image is probably larger than the .vmdk, which is a compressed format.

Mac users can also perform this conversion using Oracle’s VirtualBox, by running the following commands in Terminal:

 cd /Applications/VirtualBox.app/Contents/MacOS/ 
sudo ./VBoxManage clonehd drive.vmdk drive.raw –format RAW

With a converted VMware image, is there anything else I need to know?

Yes – you might still have issues getting it to work. Our recommendation is always to create a new system inside the ElasticHosts servers and install what you need, and send over data. Windows guests in particular dislike having their virtual hardware swapped around, so there are few guarantees that you’ll have a reliable system after conversion. That said, we recommend:

  1. Remove VMware Tools before you shut down for conversion. This is the most important step.
  2. Make sure when you run the converted file, you set the number of cores to at least two. This is in the advanced options for the server, and does seem to make Windows guests in particular more reliable.
  3. Some users have had more success with the older RealTek virtual network card than the Intel one. If you do have issues, it’s certainly worth swapping.

I don’t have a Unix/Linux system. Is there any other way to do this?

Yes – if you can boot the VM locally, you can upload a hard drive without needing to convert the image using the method described here.

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General questions


####Cloud Hosting

What are cloud servers?

The term ‘cloud’ is used to describe a number of very different products, but in our case, it refers to on-demand, scalable, virtualized servers accessible over the internet.

How do cloud servers differ from dedicated servers?

When buying a dedicated server, typically you have to pay an initial set-up fee and commit to a contract for a year or more at a higher minimum price point than a cloud server. There is usually a lead time on the hardware, and it is difficult to change the server specification as your needs evolve, forcing you to buy something large enough for your application to grow into. You pay for the server 24 hours a day, not just when you want it up and running.

Our cloud servers, on the other hand, can be deployed immediately from our easy-to-use web control panel and have no setup charge, a low minimum price point, and no commitment to a contract. As your requirements change, you can instantly scale up and down the resources you use, and can even pay-as-you-go for just the hours your servers are running.

How does cloud hosting differ from a CDN (Content Delivery Network)?

A CDN is used to distribute copies of static media content such as images and videos to the edge of the network, nearer to your customers. This enables them to download these files with lower latency and less chance of bandwidth contention. It only works for static media content, and cannot be used for dynamic content or more general compute applications in the same way as Cloud Servers.

How does cloud hosting differ from shared hosting?

Shared hosting solutions usually only give you access to your server through a web control panel, where you can manage a number of websites hosted on that server. With our cloud server, you get full adminstrator control over your server and the ability to install any software you like and configure it exactly how you wish.


####ElasticHosts

How do ElasticHosts’ Cloud Servers differ from traditional Virtual Private Servers (VPS)?

Traditional VPS providers slice up large dedicated servers to share them between customers. Typically VPS providers use a container technology such as Virtuozzo to isolate multiple users on a single server from one another whilst running a single shared instance of the operating system.

By contrast, ElasticHosts offers two types of cloud server product – KVM-based virtual machines (VMs) and Elastic Containers. Our KVM technology provides full hardware virtualisation for VM customers, enabling every user to run the operating system of their choice and offering greater flexibility and configurability than a traditional container-based VPS.

See video.

What physical infrastructure is ElasticHosts based on?

The virtualisation hosts in lon-p and sat-p have dual quad-core Xeon E5420s at 2.5GHz with 32GB of RAM and 4-6x 0.75-2TB drives each. The virtualisation hosts in lon-b have dual quad-core Opteron 2352/2378s at 2.1/2.5GHz with 32GB of RAM and 2-3x 1-2TB drives each. They run our in-house cloud hosting platform, which is built on open source technologies including Linux, qemu-kvm, LVM and iSCSI. The disks are arranged into RAID 1 pairs, and virtual disks are allocated out of this pool of RAID 1 arrays.

What services does ElasticHosts offer?

We offer a self-managed cloud hosting service. As one of our customers you have full administrator access to your virtual servers and are responsible for the configuration and management of the operating system and applications that you wish to run. We also offer Managed Cloud Servers (for complete management of your Cloud Servers) and Cloud Storage.

Do you offer domain registration and DNS?

No, this is something you need to source from a third-party supplier. Many domain registrars will bundle a free DNS service when you purchase a domain. There are also third party DNS providers, some of them with free offerings such as http://freedns.afraid.org.

Do you provide control panels such as cPanel, Plesk or PHPMyAdmin?

We provide a pre-installed cPanel image and an accompanying license (see setup guide). You can install and run any other software yourself.

Do you offer managed hosting services?

No, we only offer a self-managed service. Our infrastructure is very easy-to-use and you can install and administer it just like physical hardware. However, we can recommend partners if you would prefer a fully-managed product.

Do you have reseller or referral schemes?

Yes, please see our Reseller and Referral Partner Program for details.


####Support

Can you provide consultancy on optimising my system for performance and scalability on your platform?

Most of our customers will be able to install and configure their systems themselves, but if you have particularly specialized requirements, we can offer consultancy and systems support for $225 per hour. We can also recommend partners who can help with more general server software installation and configuration.
Contact us at sales@elastichosts.com for more information.

What Service Level Agreement (SLA) do you offer?

Our Service Level Agreement (SLA) is highly competitive, offering 100x credits for any unscheduled downtime longer than 15 minutes, up to 1 month’s credit. See our Terms of Service for more details.

What support do you offer?

We offer live chat, telephone and email support 24 hours a day, 7 days a week. We support the virtualization infrastructure, but our customers self-manage their operating system configuration and applications.
See more on our Support page.

How do you schedule planned maintenance?

Whenever possible, any planned maintenance is scheduled outside of local business hours. We will notify you of this by email at least 24 hours in advance. We will never schedule maintenance simultaneously in more than one of our sites, ensuring that they offer full redundancy to each other.


####Cloud Servers

How do I create a server?

On the top of the control panel in your account, you can follow the Add Server wizard to create a server. ![Add server wizard in the control panel](/blog/content/images/2016/05/FAQ-cloud_servers_add-server.png) We offer KVM-based Virtual Machine and auto-sizing Elastic Containers with various options for installing an OS:

  • Use a pre-installed system.
  • Self-install from a CD. There are many install CDs to choose from, for different OSes.
  • Upload your own CD and boot your server from that.

Elastic Containers are automatically created with auto-scaling SSD storage that will grow and shrink according to your server's storage needs. When you add a new VM server, make sure you create a sufficiently large drive with it to store your operating system, applications and data.

How can I update my container?

On Debian and Ubuntu, use the following commands:

apt-get update
apt-get upgrade
Under no circumstances use apt-get dist-upgrade or its equivalent on other distributions. As our containers have very specific configurations to work correctly in the shared environment, dist-upgrade will not work, or partially work, and very likely break the container permanently.

How can I reboot my container?

Rebooting a container from the control panel is simple and straightforward:

  1. Press Shutdown on the container: Elastic_Container_turned-on
  2. Press Start on the container: Elastic_Container_turned-off

Rebooting a container on command line:

  1. To use this feature, first you need to enable the Respawn feature in the advanced options on the server configuration page. Elastic_Container_respawn-feature
  2. Once Respawn is enabled, typing the command for restart on the command line from inside the container will result in the containers shutting down and then rebooting.

==Please note: initiating restart with the Respawn feature disabled will shut down the container without restarting it. ==

What are drives and servers and how do I use them?

Drives are just like physical hard disks or CDs. They store your operating system, applications and data, and are persistent across server reboots. Servers are virtual machine instances, and may have one or more drives attached to them. They are either running or powered off. When a server is running, the cloud provides VNC access. When a server is powered off, you can configure the CPU, memory, drives and IP addresses which it uses. Some of our competitors have less-flexible products in which every server has exactly one drive. Our approach is more general, allowing you to attach several drives to a single server, or building several alternative configurations which boot from the same drive. (However, only one running server can access a given drive at any one time).

How are the sizes of drives and servers measured?

Like a physical hard drive, drives are measured in gigabytes (GB). Servers have two adjustable sizes: the amount of memory (in MB) and the amount of CPU bandwidth (in core-MHz).

What is the minimum size of a single server or drive?

The smallest single server you can create is 500 core-MHz CPU, 256 MB RAM, with a 1 GB disk drive. This is typically sufficient for a Linux appliance such as a DNS server.

What is the maximum size of a single server or drive?

The largest single server you can create is 20000 core-MHz CPU, 16 GB RAM (or 8 GB in our sat-p zone), with one or more 2TB disk drives.

How many servers and drives can I have?

There is no limit to the number of servers and drives that you can have in your account.

How large a server and drive do I need?

This will depend entirely on what you plan to use your server for: everybody’s requirements vary. However, a good starting point is to configure with the same sizes as you would use if you were purchasing a physical server for your application.

This is even simpler with the Linux-based Elastic Containers: you can set the maximum value of CPU and memory for the server, and the server scales itself automatically to meet its load - and you pay only after the actual usage, not the maximum capacity!

How are my servers and drives distributed between physical hosts?

When you create a drive, it is allocated on a randomly chosen host with sufficient free space. When you start a server, our system prefers to place it on the same physical host as its drive(s). If this is possible, the server can directly access the underlying physical disk. Otherwise, if the host containing the drive is already too busy, the server will be started on a nearby host and it will access its storage by peer-to-peer iSCSI over gigabit ethernet.

One of my servers is a backup of another. Can I specify that the two servers should be allocated on different physical hosts for better resilience?

Yes, although again this is only possible through the API at present. When you create the second server, pass in avoid:server plus a space-separated list of the UUIDs of the servers you wish to avoid. As above, you can avoid particular drives too: pass in avoid:drive with a space-separated list of the drive UUIDs to avoid.


####Accessing a cloud server

How do I access and control my server?

The cloud provides basic VNC access to servers, which works from the BIOS onwards, and allows you to install, configure and recover your operating system, even if nothing is running inside your server. In normal use, you should access your server by a native method (e.g. SSH, VNC installed inside your operating system on port 5901, Windows Remote Desktop/RDP), which will provide superior performance.

What VNC software do you recommend?

Perhaps the easiest way to access your server over VNC is to click ‘Show screen’ from the control panel. This will open a VNC window in your browser. We recommend using Google Chrome or Firefox for best results.

If you prefer a dedicated client program, you’ll find that our VNC service requires a reasonably recent client. TightVNC works well on Windows, and clients based on gtk-vnc such as Vinagre work well on Linux. The RealVNC Enterprise Edition Viewer is good on Linux, Windows and MacOS if you set the “Always use best available colour quality” (or set FullColour to Yes in the Expert panel on the MacOS version of RealVNC). The Linux and MacOS versions of this are available as a free download on the RealVNC web site.

Neither the Apple Remote Desktop VNC client, Chicken of the VNC, nor JollysFastVNC work correctly on MacOS as they don’t support some of the newer protocol features which we use.

Why does my password work in VNC but not in RDP/SSH?

Please check your local keyboard settings. VNC will always enter keystrokes as if from a US keyboard, which may cause problems with some special characters. By contrast, RDP and SSH will always maintain the settings from your local keyboard.

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Networking


####Basic Networking

How can I send email from my servers? Can you lift the SMTP (port 25) block?

We are happy to lift the SMTP block so you can send email from your servers. Please email support@elastichosts.com to request this, confirming that:

  • any mailing lists you run on the servers are strictly opt-in, and
  • all messages sent to those mailing lists contain instructions on how to unsubscribe.

How can I track my bandwidth use?

A report of received, transmitted and total bandwidth for your account is shown on your billing page, with links to display traffic graphs. You can edit the URL parameters on these graphs to adjust the timeframe and offset: window = graph time duration in seconds offset = graph end distance before now in seconds width and height in pixels Per-server traffic graphs are available from the control panel. There is a link next to the VNC IP address when the server is running.

What internet bandwidth can I expect? Is this limited?

In each of our availability zones, your virtual machines are connected directly to a major ISP’s backbone network at 1Gbps speed. We do not cap or throttle the connection.

What is the difference between the virtual network cards you offer? Which do you recommend?

By default, your VM will use the Intel PRO/1000 emulated NIC, as it is the most modern and is widely supported in modern operating systems. However, wider support for the Realtek RTL8139 card means that we recommend using the Realtek emulation if you experience any problems with the Intel model: Windows XP/2003 users in particular may find that the older card is better supported on their OS.

What happens if I go over my subscribed bandwidth limit?

If you go over your subscribed bandwidth limit, then you will be charged the hourly burst rate for additional bandwidth and this will be deducted automatically from your prepay balance. When your prepay balance runs out there is a buffer of 10-20 GB which you can use. After that your servers will be automatically shut down. As your prepay balance is being used up, you will receive warning emails, letting you know you should top up (or increase your subscriptions).

Will I be charged for bandwidth between my servers?

Yes, we charge for all bandwidth usage that does not go over a private VLAN.

Do you block any network traffic?

We block outbound connections to SMTP, FTP, SSH and telnet servers to prevent abuse of our trials for sending spam or conducting dictionary attacks against other internet hosts. Port 5900 is used for running the VNC console.

My VM won’t connect to the internet – what can I do?

If you can’t connect to the internet, you can still connect to the VM using the provided VNC server. This allows you to ensure that everything is running normally, and fix any configuration issues which may be affecting the network connection. RHEL or CentOS users may find that they are affected by this known bug within their OS.


####VLAN

What is a private VLAN and why would I use it?

A VLAN acts like a private gigabit ethernet switch connecting your servers together via a second virtual ethernet card in each server. This network is isolated from the internet and other customers. Bandwidth over a VLAN is not chargeable.

How can I configure a private VLAN?

First, purchase a private VLAN subscription. Then add it to your account in the control panel. Then, edit each server’s configuration to use your private VLAN. This is under the Advanced settings.

Do private VLANs work between your availability zones?

No. A private VLAN can only be set up within a single availability zone, so any traffic sent between our different availability zones will be charged at the standard rates.


####IP address

How do I set reverse DNS for my static IP addresses?

You can set this on the control panel – simply add your desired reverse domain name into the box by the IP, and click the ‘Submit’ button.

How do I use multiple static IPs on the same server?

You will need to configure this inside your server. The networking option on the server configuration page just sets the IP address that the server is supplied by DHCP and uses for VNC. This should be the ‘primary’ IP of the server, but you can also use any other static IPs in your account if you configure these inside your server operating system.

How do I remove a static IP address from my account?

Since all the static IP addresses in your account are available to be used by all servers at any time, then you will need to stop your servers before you will be able to delete a static IP address from your account.

How do I get a static IP address?

Servers are configured with a dynamic IP by default, but you can purchase a subscription for as many static IP addresses as you need through the subscriptions page in your account. You then need to allocate the actual addresses by clicking ‘add static IP’ on the control panel, and configure the static IP in your server configuration.


####Load balancing / Clustering

How do I set up load balancing between my servers? Which tools do you recommend?

We recommend that you set up a small server in your cluster, running a load balancer, such as HAProxy or Pound, and connect it to your backend web servers over a VLAN.

How can I configure my system to fail over between your two clusters?

The easiest way of configuring failover is to use a DNS-based failover method. Set a low TTL on the A record for your website to avoid excessively long caching, and alter this to point to the backup server when the production server is down. There are third-party DNS providers who offer this kind of service as part of their DNS hosting offering.


####Security

How do I set up a firewall on my servers?

You can purchase a firewall for your server (for charges, see the Pricing page). To add a firewall to your server, from the ElasticHosts control panel, first shut down the server, then click Edit. On the Edit page, click “Enabled” next to Firewall: don’t forget to hover your mouse over the green tooltip for more information on the options available to you here.

What access do ElasticHosts staff have to my servers?

Elastichosts staff do not have access to your server passwords. The only access they have is the ability to see the VNC display, which they may use from time to time to check that your server is running.

How can I encrypt VNC connections to a server?

We do support TLS VNC using the VeNCrypt extensions, which some VNC clients support. You can enable this option through the advanced settings in the server configuration page. Note there are several different incompatible schemes for TLS on VNC. gtk-vnc/vinagre on Linux is a popular client that works with VeNCrypt.

How can I disable VNC on a server?

On the server configuration page, you can disable VNC access by leaving the VNC password field blank.

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Infrastructure


####CPU

What is the minimum and maximum CPU value for a single server?

The minimum CPU value for a single server is 500 core-MHz and the maximum CPU value is 20000 core-MHz.

What do you mean by core-MHz?

The effective speed of modern CPUs is determined both by the clock speed of the processor (in MHz) and the number of independent execution units (cores). For a given processor design, the available CPU bandwidth is roughly proportional to the product of these two. Concretely, if you create a virtual server with 2100 core-MHz of CPU allocated, you should expect performance roughly equivalent to a single core of AMD Opteron 2352 clocked at 2.1GHz, and this performance varies linearly in proportion to the core-MHz number.

How do I set the number of CPU cores?

This is under the advanced settings on the server configuration page – simlpy click Edit when your server is powered off to view and edit these settings.


####Memory

What is the minimum and maximum memory for a single server?

The minimum memory value for a single server is 256 MB RAM.

All our zones support servers running 32GB RAM, except our Sat-P zone, where the limit is 8GB.


####Storage

What is the minimum and maximum size of a single drive?

The minimum size is 1GB and the maximum size is 2 TB for a single drive.

Can I attach one drive to more than one server?

No. However, you can run filesharing protocols such as NFS or Windows File Sharing from one server to another over a private network VLAN.

How do I attach more than one drive to a server?

You can set this in the server configuration page. (Click Edit when your server is powered off to find this page).

What storage performance can I expect?

You should be able to achieve around 30-40MB/s streaming read and write performance from your virtual drives. However, contention with other users accessing the same underlying RAID arrays can result in lower performance, especially at peak times. This affects writes more than reads as we cannot safely cache disk writes as aggressively.

What is the difference between IDE, SCSI and VirtIO drives? Which do you recommend?

If you’re not sure then you should stick with the IDE emulation, which offers good performance and compatibility. However, we believe that VirtIO drive types provide the best performance, and these are what our preinstalled images use by default.

Note that our virtio drives have writeback caching enabled, so you will need Linux 2.6.32 or later, which supports barriers over VirtIO, to be able to use these safely. If you’re not using one of our recent preinstalled images, VirtIO disk drivers must be installed specifically within Windows before you can use this disk type. See our guide for switching drives to Virtio block devices.

What is dedicated disk storage, and what are the advantages?

Our normal virtual drives are allocated from RAID1 disk pairs shared between customers. This means that when one customer is heavily accessing their disks, your accesses may be slower if they happen to be on the same disk pair. If you need uncontended access to your virtual drives, we can allocate a RAID1 disk pair specifically for your use, with no other customer drives on it. This means that performance on your drives cannot be degraded by the activity of other ElasticHosts users.

What happens to my data when my server shuts down?

Data stored on your virtual drives is persistent and will be available when you restart your server, just as it would be on a physical hard disk. This means that you can install software and save data exactly as you would on a physical server, unlike some other cloud solutions.


####Scaling

How do I resize my server?

When your server is powered off, go into the server configuration page, then simply adjust the CPU and memory settings.

How do you recommend configuring server clusters appropriate for each stage in my website’s growth?

Whilst the exact answer will vary according to your web application’s architecture, we recommend the following cluster architectures to back a typical site as it grows, progressing in order:

  1. Single small server with standard disk, running entire LAMP stack
  2. Single large server with dedicated disk, running entire LAMP stack
  3. Multiple large servers in classic 3-tier web application architecture, interconnected over private network VLAN:
    1. Clustered database servers with dedicated disk
    2. Front-end application servers with standard disk
    3. Load balancer(s) running Pound, HA-proxy, etc.

Note that in the second stage a single larger server with dedicated disk will typically give better performance than splitting immediately into multiple small servers, since disk I/O is improved and there are no extra latencies from cross-network communication.

How do I scale automatically with load?

You can use our API to start and stop servers when your application detects that it needs extra computing power. Building an application which scales across multiple machines like this is done in the same way as it would be on physical hardware which you could programmatically turn on and off, but is beyond the scope of this FAQ.

How do I shrink my disk safely?

It is very important to shrink the size of your filesystem and any partitions using your operating system BEFORE trying to shrink the drive itself! If you don’t do this, you will chop the end off the filesystem when you shrink the drive leading to serious corruption.

If in doubt, we strongly advise against attempting a drive shrink because of this risk: this functionality is disabled in the web control panel to prevent accidental loss of data.

However, once you are sure it is safe to do so, you can shrink the virtual drive by shutting down the attached server and either decreasing the drive size via the API, or contacting the support team to shrink the drive as required.

How do I grow my disk?

To increase the size of your drive, shut down the server it is attached to, choose Edit for that drive in your control panel and increase the size in the dialog. After resizing the disk, you can restart your server attached to it but will then need to grow any partitions and filesystems on it to make use of the extra space. (Our pre-installed Linux images do not have partitions but just a single filesystem filling the entire drive, so it is sufficient to run resize2fs directly on the hard disk block device node to grow this filesystem).

Can I change the size of my server whilst it is running?

No. Operating systems are not able to recognise changes of this sort and would crash if we enabled them.

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