PCIe-based SSD for L2ARC?

[madilyn]

Has anyone used PCIe-based SSDs like the OCZ Z-Drive R4, Intel 910 or OWC Mercury Accelsior E2 for their L2ARCs? These seem to extract extraordinary performance for value, but I haven't seem many ZFS builds that use them. Any opinions?

I see a few caveats... For example, the Intel 910 card presents the chips as 4 discrete disks, and I'm told that there's a bug with L2ARCs larger than 2 disks. The 910 also seems to perform poorly for small file, low queue depth I/O (see benchmark: http://www.anandtech.com/show/6124/the-intel-ssd-910-review/5).

 

[drescherjm]

I would rule the OCZ drive out. It is slower than a single 840 Pro in random performance.

These seem to extract extraordinary performance for value

Remember that most consumer grade PCIe SSDs are not really PCIe devices but a raid 0 of SATA SSDs attached to a hard drive optimized SATA controller. This may be fine large sequential performance but is not always great for IOPS / small random operations.

 

[dandragonrage]

Can you hold off a few months for the upcoming native PCI-E SSD solutions? New chips like the SF3700 support PCI-E natively. Not many current PCI-E SSDs are good.