Note: "permalinks" may not be as permanent as we would like,
direct links of old sources may well be a few messages off.
Hi,
________________________________
From: drbd-user-bounces at lists.linbit.com <drbd-user-bounces at lists.linbit.com> on behalf of Lars Ellenberg <lars.ellenberg at linbit.com>
Sent: Friday, November 4, 2016 3:02 PM
To: drbd-user at lists.linbit.com
Subject: Re: [DRBD-user] CPU Util for DRBD resources
On Tue, Nov 01, 2016 at 07:02:02AM +0000, pillai bs wrote:
> Hi Experts,
>
>
> Is there a possible way to monitor CPU Util for the drbd resource.
> Actually am getting cent percent utilization even i dont have much
> load.
>
> Am maintaining my setup with three blocks one for Data, other for
> configurations and the other for logs which was logically mounted.
DRBD version?
My DRBD Version is "8.3.11 "
The stats you present below look like the "queue length" is
misaccounted. Our iostats had some problems in the past, potentially
producing such bogus results.
Also, even when correct, %util may not be what you think it is.
%100 util does not mean it cannot take any more. "I aggree"
It only means that "most of the time" a new request is submitted before
previous requests have been completed, or maybe "back to back" with the
completion.
Here "back to back" u meant it is synchronizing ??
cat /proc/drbd
version: 8.3.11 (api:88/proto:86-96)
GIT-hash: 0de839cee13a4160eed6037c4bddd066645e23c5 build by gardner@, 2012-06-26 09:38:36
0: cs:Connected ro:Primary/Secondary ds:UpToDate/UpToDate A r-----
ns:1776 nr:0 dw:1776 dr:103377 al:6 bm:0 lo:0 pe:0 ua:0 ap:0 ep:1 wo:b oos:0
1: cs:Connected ro:Primary/Secondary ds:UpToDate/UpToDate A r-----
ns:2760 nr:0 dw:2760 dr:1353 al:11 bm:0 lo:0 pe:0 ua:0 ap:0 ep:1 wo:b oos:0
2: cs:Connected ro:Primary/Secondary ds:UpToDate/UpToDate A r-----
ns:1551720 nr:0 dw:1551720 dr:8469 al:41 bm:0 lo:0 pe:0 ua:0 ap:0 ep:1 wo:b oos:0
There is nothing more to sync.
My question is
why the "drbd2" alone utilizing CPU more than drbd1/drbd0
SInce it is logicaly mounted, why not the actual "dm-9" shows very minimal util of CPU.
Hope you got my question. Thank you.
Depending on usage patterns, and network and IO backend latencies,
100% util may even be expected.
> [root at pcpha-dev-01 ~]# iostat -x 5 | grep drbd
> drbd0 0.00 0.00 0.00 0.00 0.00 0.00 0.00 858980.47 0.00 0.00 99.94
> drbd1 0.00 0.00 0.00 0.00 0.00 0.00 0.00 101.94 0.00 0.00 99.94
> drbd2 0.00 0.00 0.00 0.80 0.00 3.20 4.00 858935.49 0.25 1249.25 99.94
> drbd0 0.00 0.00 0.00 0.00 0.00 0.00 0.00 858980.46 0.00 0.00 100.00
> drbd1 0.00 0.00 0.00 0.00 0.00 0.00 0.00 102.00 0.00 0.00 100.00
> drbd2 0.00 0.00 0.00 2.80 0.00 19.20 6.86 858935.46 0.07 357.14 100.00
>
> [xxxx at xxxx]# iostat -x -d
> Linux 2.6.32-431.el6.x86_64 (xxxx) 10/31/2016 _x86_64_ (4 CPU)
>
> Device: rrqm/s wrqm/s r/s w/s rsec/s wsec/s avgrq-sz avgqu-sz await svctm %util
> sda 0.00 0.86 0.01 1.67 10.96 20.22 18.50 0.00 0.73 0.41 0.07
> dm-0 0.00 0.00 0.00 0.02 0.05 0.12 9.97 0.00 9.66 1.99 0.00
> dm-1 0.00 0.00 0.00 0.00 0.00 0.00 8.00 0.00 2.14 0.82 0.00
> dm-2 0.00 0.00 0.00 0.02 0.02 0.12 9.22 0.00 1.97 0.01 0.00
> dm-3 0.00 0.00 0.00 0.78 0.00 6.23 8.00 0.00 0.48 0.21 0.02
> dm-4 0.00 0.00 0.00 0.00 0.00 0.00 7.99 0.00 3.30 2.89 0.00
> dm-5 0.00 0.00 0.00 0.48 0.01 3.85 8.01 0.00 0.64 0.22 0.01
> dm-6 0.00 0.00 0.00 0.01 0.00 0.04 8.00 0.00 24.47 0.02 0.00
> dm-7 0.00 0.00 0.01 0.03 6.50 0.21 205.25 0.00 37.54 1.13 0.00
> dm-8 0.00 0.00 0.00 0.02 2.21 0.15 109.64 0.00 9.22 0.89 0.00
> dm-9 0.00 0.00 0.00 1.19 2.17 9.50 9.81 0.00 0.65 0.31 0.04
> drbd0 0.00 0.00 0.00 0.01 0.00 0.08 8.00 0.20 421.71 10481.54 10.45
> drbd1 0.00 0.00 0.00 0.01 0.00 0.07 7.95 0.06 76.94 12030.16 10.49
> drbd2 0.00 0.00 0.00 0.56 0.00 3.26 5.85 0.15 0.61 176.92 9.87
>
> [xxxx at xxxx]# iostat -x 5 /dev/vg1/lvdblog
> Linux 2.6.32-431.el6.x86_64 (xxxx) 10/31/2016 _x86_64_ (4 CPU)
>
>
> avg-cpu: %user %nice %system %iowait %steal %idle
> 2.21 0.00 0.75 0.00 0.00 97.04
>
> Device: rrqm/s wrqm/s r/s w/s rsec/s wsec/s avgrq-sz avgqu-sz await svctm %util
> dm-9 0.00 0.00 0.00 1.60 0.00 12.80 8.00 0.00 1.00 0.62 0.10
--
: Lars Ellenberg
: LINBIT | Keeping the Digital World Running
: DRBD -- Heartbeat -- Corosync -- Pacemaker
DRBD® and LINBIT® are registered trademarks of LINBIT
__
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