Hi there,
New to all this and am trying to get my head around IOPS (I work in IT but am new to SAN/virtualization). I can see this post being the first of many!
I have a network topology in my office that isn't virtualized, so I'm looking to move away from the server's inbuilt RAID10 array to a SAN with Fibre Channel connection.
I'm not entirely sure how we're going to implement it yet, so at present I'm on a learning quest with some old desktop hardware I've thrown together and I'm playing with FreeNAS (don't worry, this will never be put on production, we'll probably by a TrueNAS or HP or something but I want to get a full understanding of the workings of these things).
Current hardware as follows:
AMD FX 4100 Quad-Core
16GB DDR3
2x 120GB SSDs
1x 640GB HDD
2x 2TB HDDs
2 x 1TB HDDs
At present, I have the array set up with one SSD for ZIL, the other for L2ARC, 640GB for hot spare and the remaining drives mirrored and striped in a RAID10-style setup.
Couple of queries with my current setup:
Thanks.
New to all this and am trying to get my head around IOPS (I work in IT but am new to SAN/virtualization). I can see this post being the first of many!
I have a network topology in my office that isn't virtualized, so I'm looking to move away from the server's inbuilt RAID10 array to a SAN with Fibre Channel connection.
I'm not entirely sure how we're going to implement it yet, so at present I'm on a learning quest with some old desktop hardware I've thrown together and I'm playing with FreeNAS (don't worry, this will never be put on production, we'll probably by a TrueNAS or HP or something but I want to get a full understanding of the workings of these things).
Current hardware as follows:
AMD FX 4100 Quad-Core
16GB DDR3
2x 120GB SSDs
1x 640GB HDD
2x 2TB HDDs
2 x 1TB HDDs
At present, I have the array set up with one SSD for ZIL, the other for L2ARC, 640GB for hot spare and the remaining drives mirrored and striped in a RAID10-style setup.
Couple of queries with my current setup:
- With the 640GB as a hot spare, in the event of a failure of one of the 2TB drives, and that drive was, say, 750GB full, what happens? I was surprised FreeNAS allowed me to add a hot spare that was smaller than my biggest drive.
- I've read that should the ZIL SSD die, the entire pool is lost and I should mirror it. Is this right?
- The SSDs are standard and have no battery/supercapacitor for cache flushing.
- So, in theory, if I added the extra SSD for ZIL and the whole system had a redundant power supply and external UPS, it'd be pretty much power failure proof?
- Production setup requires maximum IOPS. Aside from the SAS/SATA and drive RPM debate, how can I maximise IOPS? I gather that if I got a couple of Z2 vdevs and striped them in a pool, I'd increase performance but only to the sum of the slowest drive in each vdev at best, but doesn't the same apply with striped mirrors? I mean for example if I have a volume of 2 vdevs each with 2 drives at 4TB, total storage would be the sum of the slowest performing drive in each vdev, just like with RAIDZ2, Right?
- So to put the above into practice, say I have 12 4TB drives. I can configure RAIDZ2 in 2 vdevs giving me approx. 22TB storage and up to four possible simultaneous drive failures with no data loss. Or, I can have 4 vdevs containing 3 mirrored drives, all striped. For this I'd have 16TB storage and much, much faster rebuild and performance, with the same/better redundancy?
Thanks.