09-21-2010
Disk performance problem on login
Running CentOS 5.5:
Quote:
Linux mythbox 2.6.18-194.11.3.el5 #1 SMP Mon Aug 30 16:23:24 EDT 2010 i686 i686 i386 GNU/Linux
I've come across a relatively recent problem, where in the last 2 months or so, the root disk goes to 99% utilization for about 20 seconds when a user logs in. This occurs whether a user logs in locally or via ssh. I have tried using lsof to track down the process that is pegging the disk, but no results are returned until the disk thrashing is over, and I don't get any useful results. So I'm looking for a way to proactively narrow down the problem. Here is some more info:
Quote:
# mount
/dev/hdb3 on / type ext3 (rw)
proc on /proc type proc (rw)
sysfs on /sys type sysfs (rw)
devpts on /dev/pts type devpts (rw,gid=5,mode=620)
/dev/hdb1 on /boot type ext3 (rw)
/dev/hda on /videos type xfs (rw,allocsize=256m,logbufs=4)
tmpfs on /dev/shm type tmpfs (rw)
none on /proc/sys/fs/binfmt_misc type binfmt_misc (rw)
sunrpc on /var/lib/nfs/rpc_pipefs type rpc_pipefs (rw)
Quote:
# df -k
Filesystem 1K-blocks Used Available Use% Mounted on
/dev/hdb3 23412640 18685492 3518660 85% /
/dev/hdb1 101086 48046 47821 51% /boot
/dev/hda 312440128 222170800 90269328 72% /videos
tmpfs 386724 0 386724 0% /dev/shm
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LEARN ABOUT DEBIAN
fdformat
FDFORMAT(8) System Administration FDFORMAT(8)
NAME
fdformat - low-level format a floppy disk
SYNOPSIS
fdformat [options] device
DESCRIPTION
fdformat does a low-level format on a floppy disk. device is usually one of the following (for floppy devices the major = 2, and the minor
is shown for informational purposes only):
/dev/fd0d360 (minor = 4)
/dev/fd0h1200 (minor = 8)
/dev/fd0D360 (minor = 12)
/dev/fd0H360 (minor = 12)
/dev/fd0D720 (minor = 16)
/dev/fd0H720 (minor = 16)
/dev/fd0h360 (minor = 20)
/dev/fd0h720 (minor = 24)
/dev/fd0H1440 (minor = 28)
/dev/fd1d360 (minor = 5)
/dev/fd1h1200 (minor = 9)
/dev/fd1D360 (minor = 13)
/dev/fd1H360 (minor = 13)
/dev/fd1D720 (minor = 17)
/dev/fd1H720 (minor = 17)
/dev/fd1h360 (minor = 21)
/dev/fd1h720 (minor = 25)
/dev/fd1H1440 (minor = 29)
The generic floppy devices, /dev/fd0 and /dev/fd1, will fail to work with fdformat when a non-standard format is being used, or if the for-
mat has not been autodetected earlier. In this case, use setfdprm(8) to load the disk parameters.
OPTIONS
-n, --no-verify
Skip the verification that is normally performed after the formatting.
-V, --version
Output version information and exit.
-h, --help
Display help and exit.
SEE ALSO
fd(4), setfdprm(8), mkfs(8), emkfs(8)
AUTHOR
Werner Almesberger (almesber@nessie.cs.id.ethz.ch)
AVAILABILITY
The fdformat command is part of the util-linux package and is available from ftp://ftp.kernel.org/pub/linux/utils/util-linux/.
util-linux July 2011 FDFORMAT(8)