Re: File read speed *strongly* degraded on one partition only
On Tue, 27 May 2003 08:26, Chris Metzler wrote:
> Hi. I am really befuddled with this one. I've checked the archives
> of this list for anyone reporting anything similar, I've googled, and
> haven't found anything useful.
> Yesterday, I abruptly started suffering from extremely slow disk reads
> from my /home partition. The symptoms are truly odd: not only have the
> parameters of the drive (checked through hdparm) not changed -- still
> using dma etc. -- but the problem isn't present on all the partitions
> of that drive. If I copy a large file from /home to a different partition
> on the *same drive* (which takes forever, because the read of the original
> on /home is very slow), and then read from the new copy of the file on the
> other partition, it reads about 15-16 times more quickly. The drive is not
> slow; only that partition is.
> Can anyone point me at anything that would help me figure out what's going
> on, and how to recover my lost I/O speed? What am I missing here as to why
> this would occur?
> Filesystem 1K-blocks Used Available Use% Mounted on
> /dev/hde10 56563100 49769796 6793304 88% /home
Wild guess - the 88% full may be your problem.
> So everything looks normal, the same on all the drives, until the file
> manipulation starts. A 651 MB file is copied from its location on /home
> to the first 120 GB drive, /mnt/b1; the two files are then compared to
> each other. Using "time", the copy takes 250s while the compare takes
> 255s -- more than 4 minutes.
I have found that comparing large files is done quicker by doing an md5sum on
each instead of diff. In my case the files are always on the saem ide chain