<tt><font size=2>> Hello everybody,<br>
</font></tt>
<br><tt><font size=2>Hi</font></tt>
<br>
<br><tt><font size=2>> here i come here again, this time to ask some
hint about how to monitor GPFS.<br>
> <br>
> I know about mmpmon, but the issue with its "fs_io_s" and
"io_s" is <br>
> that they return number based only on the request done in the <br>
> current host, so i have to run them on all the clients ( over 600
<br>
> nodes) so its quite unpractical. Instead i would like to know
from <br>
> the servers whats going on, and i came across the vio_s statistics
<br>
> wich are less documented and i dont know exacly what they mean. <br>
> There is also this script "/usr/lpp/mmfs/samples/vdisk/viostat"
that<br>
> runs VIO_S.<br>
> <br>
> My problems with the output of this command:</font></tt>
<br><tt><font size=2>> echo "vio_s" | /usr/lpp/mmfs/bin/mmpmon
-r 1<br>
> <br>
> mmpmon> mmpmon node 10.7.28.2 name gss01a vio_s OK VIOPS per second<br>
> timestamp:
1409763206/477366<br>
> recovery group:
*<br>
> declustered array:
*<br>
> vdisk:
*<br>
> client reads:
2584229<br>
> client short writes:
55299693<br>
> client medium writes:
190071<br>
> client promoted full track writes: 465145<br>
> client full track writes:
9249<br>
> flushed update writes:
4187708<br>
> flushed promoted full track writes:
123<br>
> migrate operations:
114<br>
> scrub operations:
450590<br>
> log writes:
28509602</font></tt>
<br><tt><font size=2>> <br>
> it sais "VIOPS per second", but they seem to me just counters
as <br>
> every time i re-run the command, the numbers increase by a bit..
<br>
> Can anyone confirm if those numbers are counter or if they are OPS/sec.<br>
</font></tt>
<br><tt><font size=2>the numbers are accumulative so everytime you run
them they just show the value since start (or last reset) time.</font></tt>
<br>
<br><tt><font size=2>> <br>
> On a closer eye about i dont understand what most of thosevalues <br>
> mean. For example, what exacly are "flushed promoted full track
write" ?? <br>
> I tried to find a documentation about this output , but could not
<br>
> find any. can anyone point me a link where output of vio_s is explained?<br>
> <br>
> Another thing i dont understand about those numbers is if they are
<br>
> just operations, or the number of blocks that was read/write/etc .
<br>
</font></tt>
<br><tt><font size=2>its just operations and if i would explain what the
numbers mean i might confuse you even more because this is not what you
are really looking for. </font></tt>
<br><tt><font size=2>what you are looking for is what the client io's look
like on the Server side, while the VIO layer is the Server side to the
disks, so one lever lower than what you are looking for from what i could
read out of the description above. </font></tt>
<br>
<br><tt><font size=2>so the Layer you care about is the NSD Server layer,
which sits on top of the VIO layer (which is essentially the SW RAID Layer
in GNR) </font></tt>
<br>
<br><tt><font size=2>> I'm asking that because if they are just ops,
i don't know how much <br>
> they could be usefull. For example one write operation could eman
<br>
> write 1 block or write a file of 100GB. If those are oprations, <br>
> there is a way to have the oupunt in bytes or blocks?</font></tt>
<br>
<br><tt><font size=2>there are multiple ways to get infos on the NSD layer,
one would be to use the dstat plugin (see /usr/lpp/mmfs/sample/util) but
thats counts again. </font></tt>
<br>
<br><tt><font size=2>the alternative option is to use mmdiag --iohist.
this shows you a history of the last X numbers of io operations on either
the client or the server side like on a client : </font></tt>
<br>
<br><tt><font size=2># mmdiag --iohist</font></tt>
<br>
<br><tt><font size=2>=== mmdiag: iohist ===</font></tt>
<br>
<br><tt><font size=2>I/O history:</font></tt>
<br>
<br><tt><font size=2> I/O start time RW Buf type disk:sectorNum
nSec time ms qTime ms RpcTimes
ms Type Device/NSD ID NSD server</font></tt>
<br><tt><font size=2>--------------- -- ----------- ----------------- -----
------- -------- ----------------- ---- ------------------
---------------</font></tt>
<br><tt><font size=2>14:25:22.169617 R LLIndBlock 1:1075622848
64 13.073 0.000 12.959
0.063 cli C0A70401:53BEEA7F 192.167.4.1</font></tt>
<br><tt><font size=2>14:25:22.182723 R inode
1:1071252480 8 6.970
0.000 6.908 0.038 cli C0A70401:53BEEA7F
192.167.4.1</font></tt>
<br><tt><font size=2>14:25:53.659918 R LLIndBlock 1:1081202176
64 8.309 0.000 8.210
0.046 cli C0A70401:53BEEA7F 192.167.4.1</font></tt>
<br><tt><font size=2>14:25:53.668262 R inode
2:1081373696 8 14.117 0.000
14.032 0.058 cli C0A70402:53BEEA5E
192.167.4.2</font></tt>
<br><tt><font size=2>14:25:53.682750 R LLIndBlock 1:1065508736
64 9.254 0.000 9.180
0.038 cli C0A70401:53BEEA7F 192.167.4.1</font></tt>
<br><tt><font size=2>14:25:53.692019 R inode
2:1064356608 8 14.899 0.000
14.847 0.029 cli C0A70402:53BEEA5E
192.167.4.2</font></tt>
<br><tt><font size=2>14:25:53.707100 R inode
2:1077830152 8 16.499 0.000
16.449 0.025 cli C0A70402:53BEEA5E
192.167.4.2</font></tt>
<br><tt><font size=2>14:25:53.723788 R LLIndBlock 1:1081202432
64 4.280 0.000 4.203
0.040 cli C0A70401:53BEEA7F 192.167.4.1</font></tt>
<br><tt><font size=2>14:25:53.728082 R inode
2:1081918976 8 7.760
0.000 7.710 0.027 cli C0A70402:53BEEA5E
192.167.4.2</font></tt>
<br><tt><font size=2>14:25:57.877416 R metadata
2:678978560 16 13.343 0.000
13.254 0.053 cli C0A70402:53BEEA5E
192.167.4.2</font></tt>
<br><tt><font size=2>14:25:57.891048 R LLIndBlock 1:1065508608
64 15.491 0.000 15.401
0.058 cli C0A70401:53BEEA7F 192.167.4.1</font></tt>
<br><tt><font size=2>14:25:57.906556 R inode
2:1083476520 8 11.723 0.000
11.676 0.029 cli C0A70402:53BEEA5E
192.167.4.2</font></tt>
<br><tt><font size=2>14:25:57.918516 R LLIndBlock 1:1075622720
64 8.062 0.000 8.001
0.032 cli C0A70401:53BEEA7F 192.167.4.1</font></tt>
<br><tt><font size=2>14:25:57.926592 R inode
1:1076503480 8 8.087
0.000 8.043 0.026 cli C0A70401:53BEEA7F
192.167.4.1</font></tt>
<br><tt><font size=2>14:25:57.934856 R LLIndBlock 1:1071088512
64 6.572 0.000 6.510
0.033 cli C0A70401:53BEEA7F 192.167.4.1</font></tt>
<br><tt><font size=2>14:25:57.941441 R inode
2:1069885984 8 11.686 0.000
11.641 0.024 cli C0A70402:53BEEA5E
192.167.4.2</font></tt>
<br><tt><font size=2>14:25:57.953294 R inode
2:1083476936 8 8.951
0.000 8.912 0.021 cli C0A70402:53BEEA5E
192.167.4.2</font></tt>
<br><tt><font size=2>14:25:57.965475 R inode
1:1076503504 8 0.477
0.000 0.053 0.000 cli C0A70401:53BEEA7F
192.167.4.1</font></tt>
<br><tt><font size=2>14:25:57.965755 R inode
2:1083476488 8 0.410
0.000 0.061 0.321 cli C0A70402:53BEEA5E
192.167.4.2</font></tt>
<br><tt><font size=2>14:25:57.965787 R inode
2:1083476512 8 0.439
0.000 0.053 0.342 cli C0A70402:53BEEA5E
192.167.4.2</font></tt>
<br>
<br><tt><font size=2>you basically see if its a inode , data block , what
size it has (in sectors) , which nsd server you did send this request to,
etc. </font></tt>
<br>
<br><tt><font size=2>on the Server side you see the type , which physical
disk it goes to and also what size of disk i/o it causes like : </font></tt>
<br>
<br><tt><font size=2>14:26:50.129995 R inode
12:3211886376 64 14.261 0.000
0.000 0.000 pd sdis</font></tt>
<br><tt><font size=2>14:26:50.137102 R inode
19:3003969520 64 9.004 0.000
0.000 0.000 pd sdad</font></tt>
<br><tt><font size=2>14:26:50.136116 R inode
55:3591710992 64 11.057 0.000
0.000 0.000 pd sdoh</font></tt>
<br><tt><font size=2>14:26:50.141510 R inode
21:3066810504 64 5.909 0.000
0.000 0.000 pd sdaf</font></tt>
<br><tt><font size=2>14:26:50.130529 R inode
89:2962370072 64 17.437 0.000
0.000 0.000 pd sddi</font></tt>
<br><tt><font size=2>14:26:50.131063 R inode
78:1889457000 64 17.062 0.000
0.000 0.000 pd sdsj</font></tt>
<br><tt><font size=2>14:26:50.143403 R inode
36:3323035688 64 4.807 0.000
0.000 0.000 pd sdmw</font></tt>
<br><tt><font size=2>14:26:50.131044 R inode
37:2513579736 128 17.181 0.000
0.000 0.000 pd sddv</font></tt>
<br><tt><font size=2>14:26:50.138181 R inode
72:3868810400 64 10.951 0.000
0.000 0.000 pd sdbz</font></tt>
<br><tt><font size=2>14:26:50.138188 R inode
131:2443484784 128 11.792 0.000
0.000 0.000 pd sdug</font></tt>
<br><tt><font size=2>14:26:50.138003 R inode
102:3696843872 64 11.994 0.000
0.000 0.000 pd sdgp</font></tt>
<br><tt><font size=2>14:26:50.137099 R inode
145:3370922504 64 13.225 0.000
0.000 0.000 pd sdmi</font></tt>
<br><tt><font size=2>14:26:50.141576 R inode
62:2668579904 64 9.313 0.000
0.000 0.000 pd sdou</font></tt>
<br><tt><font size=2>14:26:50.134689 R inode
159:2786164648 64 16.577 0.000
0.000 0.000 pd sdpq</font></tt>
<br><tt><font size=2>14:26:50.145034 R inode
34:2097217320 64 7.409 0.000
0.000 0.000 pd sdmt</font></tt>
<br><tt><font size=2>14:26:50.138140 R inode
139:2831038792 64 14.898 0.000
0.000 0.000 pd sdlw</font></tt>
<br><tt><font size=2>14:26:50.130954 R inode
164:282120312 64 22.274 0.000
0.000 0.000 pd sdzd</font></tt>
<br><tt><font size=2>14:26:50.137038 R inode
41:3421909608 64 16.314 0.000
0.000 0.000 pd sdef</font></tt>
<br><tt><font size=2>14:26:50.137606 R inode
104:1870962416 64 16.644 0.000
0.000 0.000 pd sdgx</font></tt>
<br><tt><font size=2>14:26:50.141306 R inode
65:2276184264 64 16.593 0.000
0.000 0.000 pd sdrk</font></tt>
<br>
<br>
<br><tt><font size=2>> <br>
> Last but not least.. and this is what i really would like to <br>
> accomplish, i would to be able to monitor the latency of metadata
operations. <br>
</font></tt>
<br><tt><font size=2>you can't do this on the server side as you don't
know how much time you spend on the client , network or anything between
the app and the physical disk, so you can only reliably look at this from
the client, the iohist output only shows you the Server disk i/o processing
time, but that can be a fraction of the overall time (in other cases this
obviously can also be the dominant part depending on your workload).</font></tt>
<br>
<br><tt><font size=2>the easiest way on the client is to run </font></tt>
<br>
<br><tt><font size=2>mmfsadm vfsstats enable</font></tt>
<br><tt><font size=2>from now on vfs stats are collected until you restart
GPFS. </font></tt>
<br>
<br><tt><font size=2>then run :</font></tt>
<br>
<br><tt><font size=2>vfs statistics currently enabled</font></tt>
<br><tt><font size=2>started at: Fri Aug 29 13:15:05.380 2014</font></tt>
<br><tt><font size=2> duration: 448446.970 sec</font></tt>
<br>
<br><tt><font size=2> name
calls time per call total
time</font></tt>
<br><tt><font size=2> -------------------- -------- --------------
--------------</font></tt>
<br><tt><font size=2> statfs
9 0.000002
0.000021</font></tt>
<br><tt><font size=2> startIO
246191176 0.005853 1441049.976740</font></tt>
<br>
<br><tt><font size=2>to dump what ever you collected so far on this node.
</font></tt>
<br>
<br><tt><font size=2>> In my environment there are users that litterally
overhelm our <br>
> storages with metadata request, so even if there is no massive <br>
> throughput or huge waiters, any "ls" could take ages. I
would like <br>
> to be able to monitor metadata behaviour. There is a way to to do
<br>
> that from the NSD servers?</font></tt>
<br>
<br><tt><font size=2>not this simple as described above. </font></tt>
<br>
<br><tt><font size=2>> <br>
> Thanks in advance for any tip/help.<br>
> <br>
> Regards,<br>
> Salvatore_______________________________________________<br>
> gpfsug-discuss mailing list<br>
> gpfsug-discuss at gpfsug.org<br>
> </font></tt><a href="http://gpfsug.org/mailman/listinfo/gpfsug-discuss"><tt><font size=2>http://gpfsug.org/mailman/listinfo/gpfsug-discuss</font></tt></a><tt><font size=2><br>
</font></tt>