Is QoS compatible with pNFS in cDOT8.3 and cDOT8.3.1?

[Dong_Chen]

IHAC is test QoS in cDOT831P1. I found the TR-4211 of performance primer cDOT8.3(Page18)

"QoSpolicies are applicable to all supported protocols, including NFS, SMB, SAN, iSCSI, and FCoE. Starting in clustered Data ONTAP 8.3, NFS 4.1 is supported.

Note:  QoS is not compatible with NFS 4 prior to clustered Data ONTAP 8.3.

         QoS is not compatible with pNFS in clustered Data ONTAP."

So I have a test of QoS and pNFS. It seems that the QoS policy group works in the pNFS access. Both in the direct LIF mount or the indirect LIF mount, the QoS throughput did limit the IO. 

So, what does the incompatibility between QoS and pNFS ly in, the limitation or something else? Or QoS is supported with nNFS?

Here are the output,

step 1, enable nfsv4,v4.1,v4.1-pnfs,

cluster1::*> nfs show -fields  v4.0,v4.1,v4.1-pnfs  -vserver svm1

vserver v4.0    v4.1    v4.1-pnfs

------- ------- ------- ---------

svm1    enabled enabled enabled

cluster1::*> vol show -fields qos-policy-group  -volume vol1

vserver volume qos-policy-group

------- ------ ----------------

svm1    vol1   qp1                                         -> QoS policy group “qp1” with the limitation of 1MB/s

cluster1::*> qos policy-group show

Name             Vserver     Class        Wklds Throughput

---------------- ----------- ------------ ----- ------------

qp1              svm1        user-defined 1     0-1MB/s

[root@rhel1 /]# mount -t nfs -o vers=4.1 svm1:/vol1 /vol1             -> mount with 4.1 option in RHEL6.5 host

[root@rhel1 /]# mount

svm1:/vol1 on /vol1 type nfs (rw,vers=4,minorversion=1,addr=192.168.0.140,clientaddr=192.168.0.61)

[root@rhel1 /]#

[root@rhel1 vol1]# dd if=/dev/zero of=q3 bs=1M count=30           

30+0 records in

30+0 records out

31457280 bytes (31 MB) copied, 70.9384 s, 443 kB/s                -> dd test the file creation while the rate without QoS limitation is 145 MB/s

[root@rhel1 vol1]# dd if=/dev/zero of=q2 bs=1M count=300          

30+0 records in

30+0 records out

314572800 bytes (315MB) copied, 272.228 s, 1.2 MB/s

cluster1::*> qos statistics volume performance show                  -> qos statistics display the throughput is around 1MB/s

Workload            ID     IOPS       Throughput    Latency

--------------- ------ -------- ---------------- ----------

-total-              -        0            0KB/s        0ms

-total-              -        0            0KB/s        0ms

-total-              -       15       981.33KB/s      1.69s

vol1-wid8129      8129       15       981.33KB/s      1.69s

-total-              -       17      1109.33KB/s      3.91s

vol1-wid8129      8129       17      1109.33KB/s      3.91s

-total-              -        6       362.67KB/s      2.56s

vol1-wid8129      8129        6       362.67KB/s      2.56s

-total-              -        0            0KB/s        0ms

-total-              -        0            0KB/s        0ms

-total-              -       13       810.67KB/s   374.49ms

vol1-wid8129      8129       13       810.67KB/s   374.49ms

-total-              -       17      1088.00KB/s      1.91s

vol1-wid8129      8129       17      1088.00KB/s      1.91s

[Renifa]

Hi,

pNFS support began in clustered Data ONTAP 8.1 for files only and continues with enhancements in clustered Data ONTAP 8.2. There is no Data ONTAP 7G/7-Mode support for pNFS. Current client support
for pNFS is very limited, but NetApp does support all clients that support pNFS and follow the RFC specifications. By default the pNFS option is enabled, but it is only active if NFSv4.0 and NFSv4.1 support also are enabled. NetApp does not currently recommend pNFS for metadata-heavy workloads. pNFS requires a client that also supports pNFS. Currently, RHEL 6.4 is the only commercial Linux distribution that has full pNFS support. Check the link for more info "http://www.cptech.com/wp-content/uploads/2014/06/Clustered-Data-on-Tap.pdf"

Thanks

[Dong_Chen · Accepted solution]

Thanks for the replying, I have got the confirmation that NFS 4.1 and pNFS are now supported in clustered Data ONTAP 8.3.1+. In clustered Data ONTAP 8.3 only NFS 4.1 was supported.