On 2011-11-02 16:06, Magnus Hagander wrote:
On Wed, Nov 2, 2011 at 16:04, Yeb Havinga<yebhavinga@xxxxxxxxx> wrote:
On 2011-11-02 15:06, Kevin Grittner wrote:
Yeb Havinga<yebhavinga@xxxxxxxxx> wrote:
I'm now contemplating not using the 710 at all. Why should I not
buy two 6Gbps SSDs without supercap (e.g. Intel 510 and OCZ Vertex
3 Max IOPS) with a IO controller+BBU?
Wouldn't the data be subject to loss between the time the IO
controller writes to the SSD and the time it makes it from buffers
to flash RAM?
Good question. My guess would be no, if the raid controller does
'write-throughs' on the attached disks, and the SSD's don't lie about when
they've written to RAM.
Doesn't most SSDs without supercaps lie about the writes, though?
I happened to have a Vertex 3, no supercap, available to test this with
diskchecker. On a ext4 filesystem (just mounted with noatime, not
barriers=off), this happenend:
# /root/diskchecker.pl -s 192.168.73.1 verify testfile
verifying: 0.00%
verifying: 30.67%
verifying: 78.97%
verifying: 100.00%
Total errors: 0
So I guess that's about as much as I can test without actually hooking
it behind a hardware controller and test that. I will soon test the
3ware 9750 with Vertex 3 and Intel 510 - both in the 3ware's ssd
compatibility list.
More info from testing software raid 1:
- with lvm mirroring, discards / trim go through to the disks. This is
where the Intel is fast enough, but the vertex 2 pro is busy for ~ 10
seconds.
-- Yeb
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