[pve-devel] Speed up PVE Backup

[Stefan Priebe - Profihost AG]

Am 16.02.2016 um 09:57 schrieb Martin Waschbüsch:
> Hi Stefan,

>> This is PVE 3.4 running Qemu 2.4
> 
> To me this looks like the compression is the limiting factor? What speed do you get for this NFS mount when just copying an existing file?

Which compression? There is only FS compression on the target side
involed. I'm not using any compression on the source side.

Writing to the NFS is very fast:
# du -sh /root/testfile
640M    /root/testfile

# dd if=/root/testfile of=/mnt/pve/vmbackup/dump/testfile bs=4M oflag=direct
159+1 records in
159+1 records out
671088620 bytes (671 MB) copied, 0,855779 s, 784 MB/s

> Anyway, first of all, if network bandwidth and backup disk space are not limiting factors, lzo compression is *way* faster than gzip.

Sure it is but that's not the problem. The problem seems to be the
dumping speed of qemu.

Stefan