Saturday, April 28, 2007

Ruby on Rails Hosting

This is a problem I've been (surprisingly) fighting with ever since I've been working with Ruby on Rails. Even though the situation has improved tremendously over the past 2 years it's still far from ideal. I am not sure if it's because insufficient demand or the increased complexity compared to hosting HTML or PHP the big hosting companies don't show much interest in Ruby hosting. Sure they list it as one of the options but the offer and support is flaky at best, many times offering only 1 rails application per account or missing ways to restart FCGI processes. Not surprisingly rails developers had to take the matter in their own hands and as a result almost any RoR hosting worth considering was started like that. I am not sure how much long term market sense it makes but looking at waiting time at slice host it really seems to be working for now.

When choosing RoR hosting the main decision you have to make is shared hosting vs. VPS. Shared hosting is usually cheaper and easier to set up but you're sharing the server with many other users and it takes only one bad neighbor to make the whole server unusable. VPS, on the other hand, is slightly more expensive and you have to set up everything your self. That gives you a lot of power and flexibility but you have to be able to configure Linux server (it's really no rocket science – there's plenty of How-To-s on the net – including this blog).

Shared Hosting

A few things to watch out for when choosing shared hosting:

  1. FCGI support – most of the hosts offer FCGI (but there are still many that offer only CGI) including an easy way of restarting FCGI processes. You really don't want to open up a support ticket any time you update you application and especially not when you fix a very urgent bug.
  2. 24/7 Support – while 24/7 support is claimed to be a standard in hosting industry I am yet to really find the host with this kind of support. That is not to say that the support doesn't matter – it really does and even if not 24/7 you should really test them out first – open up tickets outside of business hours, on public holidays, etc. and see the response time as well as helpfulness and professionalism. Many big hosting companies outsource their support offshore and all you'll get outside the working hours is “I will get a senior technician to look into the problem”. This is especially important if you're not in different timezone.
  3. Number of applications you can host under one account. This includes number of domains, number of subdomains as well as number of databases that you can create. You don't have to worry that much about the actual limits of the server here because if you're not going to utilize the resources it doesn't make them available during peak, it just means that somebody else will.
  4. DNS management tools / support. This is not so important if you have 1 application but as the number increases you will have to take care of multiple domains and multiple subdomains under each domain. With the standard shared hosting you will usually only get cPanel that lets you maintain only domains/subdomains hosting on the same server. Reseller account should come with WHM that has proper DNS management tool. Of course you have always option to host your DNS elsewhere.
  5. Disk space / bandwidth limits. Usually not a problem with U.S. hosting but most of the hosting companies in Asia still offer 100MB accounts.
  6. SSH. It's very hard if not impossible to set up your rails application without SSH access and yet I've seen several hosts (mostly in Asia) to offer ruby hosting without SSH. When I asked how to install the application they asked me for step by step instructions :-). I really don't think you want to do that.
  7. SVN hosting – not crucial but a very nice bonus. It's beneficial even if you're a sole developer as it makes your repository available online. RailsPlayground.Com even bundles this with Trac.

Looking at the list seems like there's quite a few things to watch out for. From what I've used the best seems to be the RailsPlayground.Com. They have a very reasonable reasonable support, very few limits and offer quite interesting packages. The downside is that the servers do get overloaded sometimes and then they kill off your processes. This is really bad as the user will get a Rails Application Error but the Exception Notifier will not generate anything and there won't be anything in the logs. I've had several other issues there – longer HTTP POST will generate application error – again without any trace in logs and I had some intermittent problems with file upload / download. Other then that I would recommend them as most probably the best RoR shared hosting out there.

VPS Hosting

VPS experience a stellar launch to popularity over the past year solving most of the problems of shared hosting for only slightly higher price. It had an easy job replacing dedicated hosting offering roughly the same but for 10 times higher price.

Here are some things to watch out for:

  1. 24/7 Support – even though it's all maintained by you and you're much less dependent on support, there still will be times when your VPS doesn't come back after restart or doesn't respond due to some runaway processes.
  2. Choice of Linux distributions – many hosts offer a selection of distributions like Ubuntu, Debian, RedHat, etc. You just choose your desired flavor from the menu and it's automatically installed for you. It's really helpful when you have experience with only one Linux flavor or to synchronize your installations when you have multiple servers at several hosting companies.
  3. Memory / Price ratio. The only important resource when choosing VPS is memory. Most of them come with sufficient disk space and run on multiprocessor machines but provide only limited memory. Anything below 256MB is not worth considering. You shouldn't pay more then US$ 29 for 256MB and usual price is around US$ 20. Some hosts provide burstable memory which means you can go over your memory limit if nobody else is using it. This can be very helpful during random hit surges or when processing memory extensive tasks. Be very careful as some of the hosts will mercilessly cut off any process that goes about the memory limit causing rails application error without any trace in logs (otherwise great does that). Another thing to watch out for here is SWAP. While not ideal, it can save your ass during peak requests. Some hosts don't allow any SWAP which will cause your application to crawl when the memory limit is reached.
  4. Scalability – check how easy it is to upgrade your account – either to increase memory or to add on another server. When number of users increases, adding another server is many times the only option to scale your application.

One of the best VPS providers is Slice Host providing all of the above for the lowest price on the market. So far, I've experienced only one short downtime. You can choose your Linux distribution, reinstall everything within a few minutes they have no nonsense policies, upgrades in both directions are painless. The only downside is a long waiting list if you're a new user. Another great host is Rose Hosting. They offer burstable memory and used to have very competitive pricing. I couldn't find any way to add another option to add servers to my account.

Some general things to watch out for:

  1. cancellation policy. It's very important to read and understand it as most of the hosts have ridiculous cancellation policies – like you have to cancel at least 3 months ahead, or only 10 days before the end of the month or only on Monday, Wednesday and Sunday 3 – 4 am. Also, money back guarantee is much more a dream then reality.
  2. Server location. Many people believe believe that the closer the server is to them the faster it is. I've heard many scientific explanations to this, but based on my experience there is usually no difference in access time unless it's on the same subnet (i.e. same provider) which is hardly a case. There is so many other factors (like aggregation, PC speed, last mile connection) that will affect the actual speed that for me it doesn't make any difference in speed for my servers located in the U.S. and servers located in Singapore. The problem with local (Singaporean, Malaysian :-) hosting is that it's several times more expensive, provides several times less resources (like space, bandwidth, memory, etc.) and only 9 – 5 support. I believe this is due to lack of local competition, lack of market awareness and undue local patriotism. Anyways, ...
  3. Backup – some hosts provide automatic backup for very reasonable price (e.g. Slice Host offers images for US$ 5). While most of the hosts claim to have auto backup it happened to me several times that it took them 2 days to retrieve this backup. As such you should think of your own back up strategy – one of the ways is to use Amazons AWS. Most of our customers require direct access to back up files and recovery within 30 minutes (this means that no matter what happens we have to be able get back online within 30 minutes). Another issue is frequency of back up – most of the auto back up is daily, which is far too little for any production application. Our standard is hourly backup with possibility to increase this during peak hours.

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