ZFS mirror across two enclosures?

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fields_g

Weaksauce
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Apr 9, 2011
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I'm looking at bring up an OmniOS ZFS SMB server at work for large datasets. Originally I was thinking 11x4Tb Raidz3, Mirrored ZIL, L2arc, and hotspares in an external enclosure. However, because of the IOPS boost, I am thinking that 16x4TB mirrored pairs are looking like the way to go. Then I started wondering if two enclosures (one of the mirror pairs in each) would give an appreciable boost in physical redundancy since there are separate backplanes, and power systems.... Or am I more likely to create more problems with potental cabling faults?

There is the possiblility that this eventually would morph into a two head system. Enclosures would have disks for 2 pools in them. Each head would mount a pool and monitor for the failure of the other head, if so, mount the other's pool. I understand this would need dual expanders in the enclosures.

BTW.. before anyone asks... this will be replicated to another ZFS system in another datacenter several times an hour for backup purposes.
 
You're protecting yourself a little more by going with two enclosures as you will be closer to a setup without a single point of failure. I would however recommend going with something with a little more redundancy if your plan on using 4tb drives. Mainly because the rebuild time on a 4TB drive will be significantly higher once your pool starts getting full. If you really need performance than 3way mirrors are the way to go. If that is too costly then I would think about getting smaller drives and more of them.
 
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that would be pretty fault tolerant. you can also lower your down time due to failure by having spare drives marked as such in your pool. And yes if iops is part of the equation at all mirrors are the way to go. Stay away from seagate it seems.
 
Even more redundant if you use a seperate HBA for each enclosure.
Don't just think about a drive dying, also think about a controller going south.

;)
 
That's true as well. Do post a build log I'm intrigued.
 
gigatexal said:
That's true as well. Do post a build log I'm intrigued.
Click to expand...

Will do. Been evaluating various ways of doing this for a while, but things are really taking shape.

@all -- Thanks for the feedback. I'm glad we are thinking alike.
 
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