On 08/28/2013 06:34 AM, spameden wrote:
2013/8/28 Kir Kolyshkin <[email protected] <mailto:[email protected]>>
On 08/27/2013 08:20 AM, spameden wrote:
ArchLinux wiki says:
*Warning: *Users need to be certain that kernel version 2.6.33 or
above is being used AND that their SSD supports TRIM before
attempting to mount a partition with the |discard| flag. Data
loss can occur otherwise!
So I guess it's not in the OpenVZ kernel?
I'd like to use TRIM because it increases performance to SSD
drastically!
You'd better check it with Red Hat, looking into their RHEL6
documentation.
My quick googling for "rhel6 kernel ssd discard" shows that rhel6
kernel
do support trim, they have backported it (as well as tons of other
stuff,
so this is hardly 2.6.32 kernel anymore).
I've just tested via hdparm (ofc it's not a perfect tool to test out
disk performance but still), here is what I get on the latest
2.6.32-042stab079.5:
# hdparm -t /dev/mapper/vg-root
/dev/mapper/vg-root:
Timing buffered disk reads: 828 MB in 3.00 seconds = 275.56 MB/sec
on standard debian-7 kernel (3.2.0-4-amd64):
# hdparm -t /dev/mapper/vg-root
/dev/mapper/vg-root:
Timing buffered disk reads: 1144 MB in 3.00 seconds = 381.15 MB/sec
and it's only read speed test.
I don't get why it differs so much?
My suggestion is, since this functionality is not directly related to
OpenVZ, and
we usually don't change anything in this code (unless there is a reason
to), to
try reproducing it on a stock RHEL6 kernel and, if it is reproducible,
file a bug
to red hat or, if it's not reproducible, file a bug to openvz.
Kir.
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