[NTLUG:Discuss] I/O Block Size and Slow Tape Backup
Stuart Johnston
saj at thecommune.net
Thu Sep 15 14:59:54 CDT 2005
Recently, we have been updating our servers from a 2.4 based distro to a
2.6 based version. We noticed our tape backups would not finish within
the normal alloted time. In my testing I found that 2.5G of data would
take 20m with 2.4 and 5h30m with 2.6. I tested with a Knoppix CD so
that I could easily switch kernel versions with everything else staying
the same.
I finally found that increasing the I/O block size solves the problem.
I understand that the larger blocks keep the tape streaming and
therefore faster but why the difference between kernel version? Does
2.6 use a smaller default block-size than 2.4?
Thanks,
Stuart Johnston
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