Am 19.02.10 20:50, schrieb Bob Friesenhahn:
On Fri, 19 Feb 2010, David Dyer-Bennet wrote:
Too bad, I'm getting ~1000 IOPS with an Intel X25-M G2 MLC and around
300 with a regular USB stick, so 50 IOPS is really poor for an SLC SSD.
Well, but the Intel X25-M is the drive that really first cracked the
problem (earlier high-performance drives were hideously expensive and
rather brute force). Which was relatively recently. The industry is
still evolving rapidly.
What is the problem is it that the X25-M cracked? The X25-M is
demonstrated to ignore cache sync and toss transactions. As such, it is
useless for a ZIL.
Yes, I see no difference with the X25-M with both zfs_nocacheflush=0 and
zfs_nocacheflush=1. After setting zfs_nocacheflush=1, the Mtron SSD also
performed at around 1000 IOPS, which is still useless, because the array
performs the same IOPS without dedicated ZIL.
Looking at the X25-E (SLC) benchmarks it should be able to do about 3000
IOPS, which would improve array performance.
I think I'll try one of thise inexpensive battery-backed PCI RAM drives
from Gigabyte and see how much IOPS they can pull.
Bob
- Felix
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