SSD Drives For The OS – 1 Or 2?

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Preparing to build a small replacement server (initially built in 2005)
and normally for the OS I would buy 2x500GB drives and deploy in a RAID
1 configuration. Now we have SSD drives available
– does just a single SSD drive offer the same reliability or is there advantage in deploying two in a Raid 1 config?

Also, what form factor / interface is best for the SSD OS boot device on a server M/B? Anything I should be looking for?
It seems most SSD are in laptop drive size, shape and interface – thus not a good fit into a server motherboard unless I’m missing something.
– what devices are you using?

Thanks in advance. Rob

4 thoughts on - SSD Drives For The OS – 1 Or 2?

  • There will always be advantages in using Raid 1 for OS, but to be able to give you a better response, we will need a little more information.

    We currently use SSDs on our blade servers, which uses hardware raid 1 for the OS only and most data and other applications are configured on different drives/clusters.

  • All else being equal, a RAID1 will be more reliable than a single drive, whether it’s magnetic or SSD.

    If you’re going for a RAID, you may as well also go for hot-swap drive bays, so that you can change a failed drive without downing the system. At that point you may as well ask your vendor what they suggest. The SSDs I have in a RAID1 configuration are 2.5″ drives.

    –keith

  • server motherboards don’t care what size the drives are, that’s a function of your server *chassis*. You can always put a 2.5″ drive in a 3.5″ adapter, but many modern servers are designed specifically for
    2.5″ drives, especially servers using SAS.

    example, note the two servers on the top of the closer rack. https://pierce.smugmug.com/By-Date/2012/2012-02-09/i-8WfCvLJ/0/X3/IMG_0318-X3.jpg

    those are HP DL180g6, each holds 25 2.5″ SAS hotswap drives in a 2U form factor.

    I *do* recommend getting ‘enterprise’ grade SSDs that have ‘supercaps’
    to ensure they can flush their write buffers on a power failure.

  • A drive is a drive .. ssd’s fail from time to time too. While you may not get the same rate of failure as with spinning disks, drives do fail and the ability to shift seemlessly from one drive to another automatically when using raid 1 far outweighs any disadvantages (which is basically just double the cost for storage devices).

    I would always use raid 1 on important devices.