Bug 219464
| Summary: | nfs service on server increases abnormally high iowait | ||
|---|---|---|---|
| Product: | Red Hat Enterprise Linux 3 | Reporter: | Rajdeep Sengupta <rajdeep> |
| Component: | kernel | Assignee: | Jeff Layton <jlayton> |
| Status: | CLOSED NOTABUG | QA Contact: | |
| Severity: | medium | Docs Contact: | |
| Priority: | medium | ||
| Version: | 3.0 | CC: | staubach, steved |
| Target Milestone: | --- | ||
| Target Release: | --- | ||
| Hardware: | All | ||
| OS: | Linux | ||
| Whiteboard: | |||
| Fixed In Version: | Doc Type: | Bug Fix | |
| Doc Text: | Story Points: | --- | |
| Clone Of: | Environment: | ||
| Last Closed: | 2007-07-17 10:54:11 UTC | Type: | --- |
| Regression: | --- | Mount Type: | --- |
| Documentation: | --- | CRM: | |
| Verified Versions: | Category: | --- | |
| oVirt Team: | --- | RHEL 7.3 requirements from Atomic Host: | |
| Cloudforms Team: | --- | Target Upstream Version: | |
| Embargoed: | |||
*** Bug 219465 has been marked as a duplicate of this bug. *** For the CPU iowait == idle. It's simply a (somewhat fuzzy) measure of processes that are sleeping, waiting for some I/O to come back. I'd like to refer you to this kbase article: http://kbase.redhat.com/faq/FAQ_80_5637.shtm I'm going to close this as NOTABUG, since high I/O wait isn't necessarily a bug (or even a problem). Please reopen the case if you have evidence to the contrary. |
Description of problem: The machine shows 90% iowait, and thus CPU is heavly utilized though no heavy process is running on the system. We have found that this happens once the nfs service gets started. Version-Release number of selected component (if applicable): 2.4.21-47.ELsmp nfs-utils-1.0.6-44EL How reproducible: boot the machine and run top 17:13:07 up 19:55, 2 users, load average: 1.03, 1.45, 1.51 63 processes: 62 sleeping, 1 running, 0 zombie, 0 stopped CPU states: cpu user nice system irq softirq iowait idle total 0.2% 0.0% 0.5% 0.2% 0.3% 81.1% 17.7% cpu00 0.2% 0.0% 0.2% 0.2% 0.6% 78.6% 20.2% cpu01 0.2% 0.0% 0.8% 0.2% 0.0% 83.6% 15.2% Mem: 2055236k av, 1894172k used, 161064k free, 0k shrd, 434180k buff 1332488k actv, 113116k in_d, 28584k in_c Swap: 2096440k av, 0k used, 2096440k free 1081172k cached PID USER PRI NI SIZE RSS SHARE STAT %CPU %MEM TIME CPU COMMAND 5546 root 15 0 0 0 0 SW 0.2 0.0 5:22 0 nfsd 5553 root 15 0 0 0 0 SW 0.2 0.0 5:34 1 nfsd 5552 root 15 0 0 0 0 SW 0.1 0.0 5:15 1 nfsd 20119 root 15 0 1092 1092 888 S 0.1 0.0 0:01 0 top 20265 root 15 0 1088 1088 884 R 0.1 0.0 0:00 1 top 1 root 15 0 300 300 240 S 0.0 0.0 0:05 1 init 2 root RT 0 0 0 0 SW 0.0 0.0 0:00 0 migration/0 3 root RT 0 0 0 0 SW 0.0 0.0 0:00 1 migration/1 4 root 15 0 0 0 0 SW 0.0 0.0 0:05 1 keventd 5 root 34 19 0 0 0 SWN 0.0 0.0 0:00 0 ksoftirqd/0 6 root 34 19 0 0 0 SWN 0.0 0.0 0:00 1 ksoftirqd/1 9 root 15 0 0 0 0 SW 0.0 0.0 0:03 1 bdflush 7 root 15 0 0 0 0 SW 0.0 0.0 2:19 1 kswapd 8 root 15 0 0 0 0 SW 0.0 0.0 0:00 0 kscand 10 root 15 0 0 0 0 SW 0.0 0.0 0:37 0 kupdated 11 root 25 0 0 0 0 SW 0.0 0.0 0:00 0 mdrecoveryd 18 root 25 0 0 0 0 SW 0.0 0.0 0:00 0 scsi_eh_0 21 root 15 0 0 0 0 SW 0.0 0.0 0:03 1 kjournald 76 root 15 0 0 0 0 SW 0.0 0.0 0:00 0 khubd 667 root 15 0 0 0 0 SW 0.0 0.0 1:00 0 kjournald 668 root 15 0 0 0 0 SW 0.0 0.0 0:21 1 kjournald 669 root 15 0 0 0 0 SW 0.0 0.0 2:22 1 kjournald 670 root 25 0 0 0 0 SW 0.0 0.0 0:00 1 kjournald 671 root 15 0 0 0 0 SW 0.0 0.0 0:50 0 kjournald 672 root 15 0 0 0 0 SW 0.0 0.0 0:00 1 kjournald 673 root 15 0 0 0 0 SW 0.0 0.0 0:00 0 kjournald 674 root 15 0 0 0 0 SW 0.0 0.0 0:00 0 kjournald 675 root 15 0 0 0 0 SW 0.0 0.0 0:00 1 kjournald 676 root 15 0 0 0 0 SW 0.0 0.0 0:03 0 kjournald Steps to Reproduce: 1. 2. 3. Actual results: load average exceeds 1, though no process is running Expected results: load average should be low, and iowait should be near 0% Additional info: