To RAID or not?

monaghan · 24th April 2008

Just curious as to what others do.

I'm just about to order another dedicated server as a general purpose cPanel hosting server, most of the offers here don't have a second drive or RAID as standard.

Presently some of my current boxes have single drives others have hardware RAID1.

What do others do? Single drive, dual drive - no RAID, dual drive - software RAID1, dual drive - hardware RAID1, other?

When building servers over the years in corporate systems, I've always gone for hardware RAID with hot spare drives, but have very infrequently seen drive failures. Is a hardware RAID worth it for general hosting purposes?

Cyberprog · 25th April 2008

It's a time thing to be honest, how much time will you lose if a hard drive dies and you have to rebuild from bare metal?

Superracks · 25th April 2008

What (financial) effort do you have to make to buy a decent hardware raid set, and what (financial) effort will it take to please customers that are out of service for (at least) hours after a hard drive failure?

Most measures are taken for what never happens. Just be content having fall back that you might never need.

Just go for the raid setup. It costs hardly anything and give you a lot of security.

markcastle · 25th April 2008

We don't have a single server that isn't at least mirrored hardware raid... not even machines that we use for our own personal sites.

James[UH] · 25th April 2008

RAID all the time.

RAID1 generally, i.e. redundancy.

Our new powerful VPS boxes are running SAS disks as RAID10.

Its of course no replacement for backups. I've had a RAID card corrupt the boot sector of disks, main data was fine, but it takes a while to shoe horn everything together to recover data in those scenario's.

othellotech · 25th April 2008

it depends. RAID only means you *might* keep online or *maybe* not lose data in the event of a drive failure.

web hosting can be very hard on disk drives, how quick they fail seems directly related to the amount of heat generated inside the server, and how much work the server does (ie how loaded you make the box)

the absolute worst thing you can do is partition up raid-1 and then let cpanel do it's backups to a separate partition on teharray - thats a g'teed way to fvckup the disks in very short order

IME drive failure, whilst it does happen, is an infrequent problem but worth protecting against, much more regular are clients deleting their webiste files, which no amount of raid will help with.

Superracks · 25th April 2008

The other circumstances kept fixed, raid with data protection just gives you an extra shot of securing data, and it hardly costs anything compared to the rest of the hardware.

nitrohosting · 25th April 2008

Quote:

and it hardly costs anything compared to the rest of the hardware.

Fully agree with this - it's usually such a small increase in the overall price it would be silly not to do it (unless you're already running mirrored systems or something else).
Kris

monaghan · 25th April 2008

Thanks,

My gut feel was to rent a box with hardware RAID1. How reliable is software RAID these days? (more specifically Linux/CentOS).

Main reason for asking the question is that most people advertising here seem to be offering RAID as an option rather than as standard.

I'm also fully aware of the need for backups, when I started as a sysadmin, backups were whole day's job feeding the VAX with 1/2 inch tapes

TDMWeb · 25th April 2008

If the budget allows a chassis that can take just 2 disks, my preference would be to use the second disk for regular backup, not for RAID, as it will enable me to recover from more scenarios. Ideal is of course RAID plus a backup disk, but chassis that take 3+ disks are more expensive. I have also read plenty of stories of screwed up RAID arrays...

adamsmith · 25th April 2008

Hardware RAID 1 *minimum* then off-server backup as regularly as disk i/o capacity allows.

Just because you've never been in a car crash, it doesn't stop you wearing your seatbelt!

Like the others, we have very few machines without RAID and they're all legacy dedicated servers. We don't provision anything new with less than 2 drives, it's just not worth the potential hassle.

Cranky · 25th April 2008

We insist on RAID1 as a minimum for anything we manage for clients, RAID5/10 minimum for our own stuff (shared hosting, VPS, etc.). Unmanaged clients we leave this to their discretion but always advise them to go with RAID if they're using the server for anything which would be hurt by the time it takes to restore from backups.

James[UH] · 25th April 2008

Hardware RAID is very reliable. We happily use 3ware cards all day long with minimal fuss.

Karl · 25th April 2008

Not had a single box without RAID for years now, not built one for about 5 years without hardware RAID (and the one we did, were for customers that insisted on it for their colo boxes we built them). We tend to have RAID-1 + 3rd drive for local backups, plus off server backups. Keeps things ticking along nicely. The problem with software RAID (and cases without hotswap) is that you're going to have downtime when a drive fails, regardless of running RAID, as you're going to need to take the server down to get it to recognise the new drive or to physically get it in the machine.

LeaUK · 26th April 2008

Quote:

Originally Posted by TDMWeb

If the budget allows a chassis that can take just 2 disks, my preference would be to use the second disk for regular backup, not for RAID, as it will enable me to recover from more scenarios. Ideal is of course RAID plus a backup disk, but chassis that take 3+ disks are more expensive. I have also read plenty of stories of screwed up RAID arrays...

Yes an interesting and alternative viewpoint. I'm also considering this approach as it's rather 'swings and roundabouts' with 2 drive systems.

Lea