Hi, SPM hosts produce ~ 2000 iops, some times even more, every 2 seconds. This is probably because the periodic inbox reads are being done as the following: dd if=[path_to_inbox] iflag=direct bs=512 count=2000, while the total size of it is only 1M This situation heavily impacts customers SAN. Thanks, Vladik
fixed by http://git.engineering.redhat.com/?p=users/dkenigsb/vdsm.git;a=commitdiff;h=f9fdc5f1621f229ce5c045536d86f3e9e5217d4b
verified with vdsm22-4.5-63.13.el5_6, Device: rrqm/s wrqm/s r/s w/s rsec/s wsec/s avgrq-sz avgqu-sz await svctm %util sda 0.01 45.52 0.03 20.20 0.68 525.75 26.02 0.20 9.81 5.42 10.97 sda1 0.00 0.00 0.00 0.00 0.00 0.00 13.33 0.00 4.26 4.09 0.00 sda2 0.01 45.52 0.03 20.20 0.68 525.75 26.03 0.20 9.81 5.42 10.97 dm-0 0.00 0.00 0.04 65.72 0.68 525.75 8.01 1.20 18.22 1.67 10.97 dm-1 0.00 0.00 0.00 0.00 0.00 0.00 8.00 0.00 5.14 1.31 0.00 dm-14 0.00 0.00 1.00 0.00 8.03 0.00 8.00 0.00 0.02 0.02 0.00 dm-34 0.00 0.00 0.99 0.01 7.93 0.94 8.85 0.00 3.11 0.02 0.00 dm-15 0.00 0.00 0.44 0.00 3.44 0.00 7.75 0.00
should be re-verified for 5.7
Please provide a technical note for this bugzilla in the "Technical Notes" field, or an indication that it is not to be documented in the errata text.
Technical note added. If any revisions are required, please edit the "Technical Notes" field accordingly. All revisions will be proofread by the Engineering Content Services team. New Contents: C: On Red Hat Enterprise Linux 5.6 hosts that held the SPM role performed additional I/O operations when periodically querying their inbox. C: The additional I/O operations resulted in performance degradation in environments that were backed by SAN storage. F: As of the vdsm22-4.5-63.14.el5_6 package vdsm does not perform additional un-necessary I/O when it periodically polls the inbox. R: The SPM uses less I/O operations. Text: Hosts that held the SPM role performed additional I/O operations when periodically querying their inbox. The additional I/O operations resulted in performance degradation in environments that were backed by SAN storage. With this update, VDSM does not perform additional un-necessary I/O when it periodically polls the inbox. As a result, I/O overhead on the SPM is reduced.
Technical note updated. If any revisions are required, please edit the "Technical Notes" field accordingly. All revisions will be proofread by the Engineering Content Services team. Diffed Contents: @@ -1,6 +1 @@ -C: On Red Hat Enterprise Linux 5.6 hosts that held the SPM role performed additional I/O operations when periodically querying their inbox. +Hosts that held the SPM role performed unnecessary I/O operations when periodically querying their inbox. The additional I/O operations resulted in performance degradation in environments that were backed by SAN storage. With this update, VDSM does not perform unnecessary I/O operations when it periodically polls the inbox. As a result, I/O overhead on the SPM is reduced.-C: The additional I/O operations resulted in performance degradation in environments that were backed by SAN storage. -F: As of the vdsm22-4.5-63.14.el5_6 package vdsm does not perform additional un-necessary I/O when it periodically polls the inbox. -R: The SPM uses less I/O operations. - -Text: Hosts that held the SPM role performed additional I/O operations when periodically querying their inbox. The additional I/O operations resulted in performance degradation in environments that were backed by SAN storage. With this update, VDSM does not perform additional un-necessary I/O when it periodically polls the inbox. As a result, I/O overhead on the SPM is reduced.
Technical note updated. If any revisions are required, please edit the "Technical Notes" field accordingly. All revisions will be proofread by the Engineering Content Services team. Diffed Contents: @@ -1 +1 @@ -Hosts that held the SPM role performed unnecessary I/O operations when periodically querying their inbox. The additional I/O operations resulted in performance degradation in environments that were backed by SAN storage. With this update, VDSM does not perform unnecessary I/O operations when it periodically polls the inbox. As a result, I/O overhead on the SPM is reduced.+Hosts that held the Storage Pool Manager (SPM) role performed unnecessary I/O operations when periodically querying their inbox. The additional I/O operations resulted in performance degradation in environments that were backed by SAN storage. With this update, VDSM does not perform unnecessary I/O operations when it periodically polls the inbox. As a result, I/O overhead on the SPM is reduced.
Since the problem described in this bug report should be resolved in a recent advisory, it has been closed with a resolution of ERRATA. For information on the advisory, and where to find the updated files, follow the link below. If the solution does not work for you, open a new bug report. http://rhn.redhat.com/errata/RHBA-2012-0169.html