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Backup to disk slower than backup to tape
New 7.4 networker install on a new 10Gb HP DL 380 G5 Dedicated Backup Server (no other apps running) RHEL 5 box. Ran my first test backup from a 300Gb SQL app to a 1 Tb fiber attached SAN and the write speed, according to the Management Console indicates it's slower (about 7 MB/sec) than our backup to our Qualstar Tape Jukebox (About 11 MB/sec).
Ran hdparm with good results, but I know there is a lot more to it than that. I also know there is a lot on this forum about tweaking and speed tests, but at this point, I am totally confused. Doesn't help that I am a Linux newbie either.
Any quick suggestions on where to look. Nic's and switches are GB and hard wired on speed and duplex.
Ran hdparm with good results, but I know there is a lot more to it than that. I also know there is a lot on this forum about tweaking and speed tests, but at this point, I am totally confused. Doesn't help that I am a Linux newbie either.
Any quick suggestions on where to look. Nic's and switches are GB and hard wired on speed and duplex.
- We have been able to determine that part of the problem has to do with the fact that we are not getting the network throughput on our Gigabit nics that we thought we should. Just doing some basic file moves indicates that things are running at the equivelent of 100Mb speeds.
Saw where there were a number of posts about performance with embedded Broadcom Gigabit Nics. Tried a few of the Linux tweaks to expand the TCP/IP Window size but not much luck. Switches and nics all say everything is is 1Gb. but doesn't seem to be going that fast.
Anybody have any info on these performance issues with the embedded Broadcom nics??
Thanks
IKP1
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Posted December 10th, 2008 00:00
Have you established the transfer speed from the backup server to the storage ? Setup ftp on the server if not already done so and from the SQL server ftp a large file (at least 1GB) to the backup server (writing to a directory on the SAN storage).
Also, if there is sufficient NON SAN attached storage on the backup server, try repeating the tests to this. This test should allow you to isolate where the performance drop is.
IKP