Debating on if I should use a 16gb USB drive for my Solaris 11 Express SAN server. I intend to use Deduplication which I believe may be IO intensive for the DB. Though I can't be sure.

The SAN server is expected to be on 24/7 for a number of years. Should I somehow if possible use multiple USB drives and mirror the OS? Is read/write speed a concern? Some drives are 10MB/s write 5MB/s read. Some are 25MB/s R/W.

I intend to add a couple SSDs for ZIL and L2ARC at a later date.

Someone had previously suggested I simply install the OS onto the storage drives in the server. 4x 300gb 15k SAS 6x 2TB 5400rpm SATA.

But I'm not sure how to size the partitions on those disks and if having the OS on them adds some layer of complexity such as when/if I decided to grow the pool by pulling disks and adding larger capacity ones.


Use a SATA Disk-on-Module (DOM) and place it directly onto one of the motherboard SATA ports. Go one step further and get two and mirror them. It's basically an SLC SSD unit in a small form factor. Much better than using a single USB key.

Use the remaining drives for your data pools.

  • To mirror they'd have to be hardware mirrored or can Solaris software raid the OS drive? – Garuda Jun 6 '11 at 21:41
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    Solaris ZFS is a software RAID. – ewwhite Jun 6 '11 at 23:30

Some servers come with an internal USB port, directly mounted onto the motherboard, for booting and running ESXi. Your idea sounds similar except you want to boot and run Solaris 11 as a kind of storage appliance. The read and write speed of USB isn't that important because it would hardly be used except on initial installation and on boot. This would allow you to dedicate your SAS/SATA slots and large drives to useful data storage.

The idea is okay in theory but in practice it's very risky. I would never put a server into 24/7 production without mirroring the boot disks. Booting off USB is nowhere near as well-tested as booting off dedicated storage, and you'd probably get no support from Oracle if things went pear-shaped. There are also some very dodgy USB flash drives out there so you run the risk of using unreliable parts in the first place.

That said, one great benefit of using ZFS for your data pool(s) is that all of the metadata is self-contained. If your USB experiment failed, at least you could move your disks and import your data onto a different server. Whether your SLA can support this kind of downtime is a question for you.

  • Oracle offers a Live USB image with the distro for Solaris 11 Express. Is that not some indication that it's useful.. Or is a Live USB only a testing method. I would be using the internal OS usb port on the server. Adding two physical drives adds a big of complexity. Raid card, heat, noise, etc. hrm. – Garuda Jun 6 '11 at 21:41
  • @Garuda: Yes it's certainly a good idea in theory, but it is unproven. One rule I follow for production is: never be the first or last person to do something. If I were doing this, I'd assume that the usb drive(s) would fail at some point and plan accordingly. I'd also not expect upgrades, patches etc to work at all unless tested. – Tom Shaw Jun 6 '11 at 23:50

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