Hello list,
I've been performance testing Amanda, trying to get the setup ready for
prime-time, but I'm having an issue getting my read speeds from tape to
get even to 6MB/s. My writes are about 12.7MB/s, which is what the tape
drive boasts (12-24MB/s normal and 2:1 compression, respectively). But,
my reads seem to hover around 5.5MB/s. I ran some dd tests, which show
the data being pulled off at 11.7MB/s, and I'm not quite sure how to
tell what amrestore is doing that is causing the performance drop off.
Here are the tests I ran; any help is appreciated.
[EMAIL PROTECTED] dd if=/dev/nst0 of=/home/restores/foobar bs=256K
count=10000G
10308+0 records in
10307+0 records out
2701918208 bytes (2.7 GB) copied,
230.539 seconds, 11.7 MB/s
[EMAIL PROTECTED] amrestore -r /dev/nst0 hostname /foo/bar
[EMAIL PROTECTED] stat /home/restores/hostname._foo_bar.20071216.0.1.RAW
File:
`home/restores/hostname._foo_bar.20071216.0.1.RAW'
Size: 2836922368 Blocks:
5546275 IO Block: 131072 regular file
Device: 908h/2312d Inode:
13 Links: 1
Access: (0640/-rw-r-----) Uid:
( 34/ backup) Gid: ( 34/ backup)
Access: 2007-12-18
12:50:15.000000000 -0500
Modify: 2007-12-18
12:58:40.000000000 -0500
Change: 2007-12-18
12:58:40.000000000 -0500
So, ~8 minutes for a 2.7GB file = ~5.7MB/s. I saw similar performance
when retrieving a DLE that spanned 6 chunks (~5.3MB/s) No errors or
anything in my amrestore logs, just start and stop times. I'm kind of
at a loss as to what would be causing this, unless my calculations (
size / time ) aren't valid? Thanks.
Best Regards,
Ryan
--
Ryan Steele
Systems Administrator
The Archer Group
