ekke85 wrote (2010/08/05):
> slow. It writes at 22mb/sec. The drives should be able to do a lot more
> then that. I have to backup 11TB that takes a couple of days to
Try tar -cf /dev/null /data-with-11-tb and you will see, if the
bottleneck is data source, or something else. How many files do
you have here?
> The spooling attribute was not enabled, I have enabled it now.
Yes, attribute spoolig is good thing too. However, data spooling
is more important, as i said before.
> ]# dd if=/dev/zero of=/home/bigfile bs=1M count=10000
> 10000+0 records in
> 10000+0 records out
> 10485760000 bytes (10 GB) copied, 189.551 seconds, 55.3 MB/s
Very slow. My spooling system says 372 MB/s, which is for spooling
4 parallel backups and one writing thread to LTO-3 tape. With 55 MB/s,
you can do at most one backup at a time, and the tape is still
"undernourished" (if write speed would equal to read speed)..
> This is writing that 10gb file with tar to tape:
> ]# time tar -czf /dev/Drive1 /home/bigfile
> tar: Removing leading `/' from member names
No, it was not tar, but a gzipped tar, where source was just zeros...
I expect, that you wrote on the tape just about 10 MB and you could
not say, what you tested more: Reading speed, processor speed, or
tape write speed.
> The 11Tb I have to backup is on a NetApp, the NetApp is mounted via
> NFS on the backup host and is getting the data from there to write to disk.
Which role NetApp plays here? NFS is not very good ticket to the speed...
--
Rudolf Cejka <cejkar at fit.vutbr.cz> http://www.fit.vutbr.cz/~cejkar
Brno University of Technology, Faculty of Information Technology
Bozetechova 2, 612 66 Brno, Czech Republic
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