Another potential issue.. is your backup software DAR capable/enabled? Which ndmp version are you running for your backups?
-----Original Message----- From: owner-toasters@mathworks.com [mailto:owner-toasters@mathworks.com] On Behalf Of A Darren Dunham Sent: Friday, September 19, 2008 1:13 PM To: toasters@mathworks.com Subject: Re: Test tape read speed
On Fri, Sep 19, 2008 at 12:57:25PM -0400, Bill Holland wrote:
You can use 'mt' to mount a tape, enable diagnostics, and some
rudimentary
testing of the device. If you are using ndmp to perform the restore, you can enable debugging ('ndmpd debug 70' for max info) to see if there are any issues there.
Yeah. Tape motion works fine. I just wanted to see if I could direct OnTap to read the tape rather than deal with netbackup.
While netbackup/NDMP is restoring the file, I see very slow reads on sysstat, but I don't know if that's an NDMP issue or a tape read issue.
sysstat could be helpful during the restore to try to determine any bottlenecks on the filer end. Also, the syslog for any SCSI
Restores will be slower than backups. I don't know the max's for the FAS6070, but when we had an R200 we saw that we could run about
200MB/sec
backups with the CPUs at 100%.
I can't get near that on the LTO-3. I never get faster than 80MB/s. The restore is around 100 KB/s.
CPU NFS CIFS HTTP Net kB/s Disk kB/s Tape kB/s Cache in out read write read write age 54% 803 46 0 10642 5422 19045 15465 193 0
60
18% 224 1 0 1330 5169 13065 13240 193 0
60
22% 636 0 0 7691 6498 18857 12320 64 0
60
20% 673 0 0 8540 6608 23073 19397 129 0
60
29% 501 0 0 7063 5842 14262 29822 64 0
60
24% 520 105 0 11136 5959 15357 4519 258 0
60
I'm actually trying to restore a single 100K file. I assume that it has to read through some of headers at the beginning of the tape, but it was sure slow doing it.