Hi Kevin, Meg, Nathan,
I'm interested in some of the details about how you're hitting this with
an eye to reproducing. Could you share any details about the following:
- Interconnect
- Client count
- Workload
Thanks!
-Aaron
On 12/8/20 1:46 PM, Kevin M. Hildebrand wrote:
We appear to be tripping over the same issues reported recently by
Tung-Han Hsieh and Simon Guilbault, namely that cur_grant_bytes is
being reduced to a very small value and causing abysmal performance.
For example, OSTs 0, 1, and 4 are having poor performance on this
client running Lustre 2.12.5:
# lctl get_param osc.*.cur_grant_bytes
osc.lustre10-OST0000-osc-ffff8e47dc02a800.cur_grant_bytes=802542
osc.lustre10-OST0001-osc-ffff8e47dc02a800.cur_grant_bytes=924204
osc.lustre10-OST0002-osc-ffff8e47dc02a800.cur_grant_bytes=11076653
osc.lustre10-OST0003-osc-ffff8e47dc02a800.cur_grant_bytes=108098653
osc.lustre10-OST0004-osc-ffff8e47dc02a800.cur_grant_bytes=797559
osc.lustre10-OST0005-osc-ffff8e47dc02a800.cur_grant_bytes=4719258
osc.lustre10-OST0006-osc-ffff8e47dc02a800.cur_grant_bytes=4898757
osc.lustre10-OST0007-osc-ffff8e47dc02a800.cur_grant_bytes=10747719
osc.lustre10-OST0008-osc-ffff8e47dc02a800.cur_grant_bytes=315019599
osc.lustre10-OST0009-osc-ffff8e47dc02a800.cur_grant_bytes=597198336
osc.lustre10-OST000a-osc-ffff8e47dc02a800.cur_grant_bytes=278803109
osc.lustre10-OST000b-osc-ffff8e47dc02a800.cur_grant_bytes=1335800831
osc.lustre10-OST000c-osc-ffff8e47dc02a800.cur_grant_bytes=795705344
osc.lustre10-OST000d-osc-ffff8e47dc02a800.cur_grant_bytes=1335052800
osc.lustre10-OST000e-osc-ffff8e47dc02a800.cur_grant_bytes=474925228
osc.lustre10-OST000f-osc-ffff8e47dc02a800.cur_grant_bytes=1424795647
From the previous discussion, the recommendation seems to have been to
run
lctl set_param -P osc.*.grant_shrink=0 on the client. Are there any
downsides to doing this?
Should I just blindly do this on all of my Lustre clients?
A little more insight into what's going on here would be appreciated.
Thanks,
Kevin
--
Kevin Hildebrand
University of Maryland
Division of IT
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