Red Hat Bugzilla – Bug 48283
Write() system call slow down when filesystem full
Last modified: 2007-04-18 12:34:36 EDT
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Description of problem:
When I make a big file(ex. 500Mbyte or more) to make filesystem be full
and add more data onto it, the system response becomes slow.
Steps to Reproduce:
1.compile additional program
2.run it(for 5minites).
3.if it's stopped because of write() error(=filesystem full), stop and rerun it.
Actual Results: Write() system call takes 2000ns or so.
Expected Results: Write() system call should return immediately upto 5ns.
Normal kernel(Linus released, not patched by redhat) do so.
We tested it on the redhat kernel from 2.4.2-2 to 2.4.3-12, and got
same results. Normal kernel(Linus released) 2.4.2 to 2.4.5
doesn't have this issue.
The reason we think this is problem, for example, when syslog daemon
writes much system log into syslog file(and filesystem is full),
system load becomes higher and higher. Now we have this phenomenon.
We know we might avoid this to avoid filesystem full someway, but
why normal kernel doesn't have this issue?
Created attachment 23147 [details]
test program about this issue.