Copy speed (rsync between ZFS and UFS)

A

arapaima

I'm backing up files from a broken down system using a memstick and an additional harddrive.

- Three disks in a ZFS raidz pool which I've.
- One disk with a fresh UFS filesystem used for backing up files.

I'm using rsync -avz on a FreeBSD live CD for copying files to the UFS filesystem, but getting incredbly slow speeds. zpool iostat gives me reads around 7MB.

Is there any way of speeding up this process?
 
You can lose the "z" (compression) option since you're syncing to a local drive. My experience has been that compression works best over slower remote links. If your gstat is not in the upper 90%, then you might want to try running multiple instances of rsync for different directories as opposed to using a single rsync instance for an entire filesystem.
 
gstat shows the drives to be quite stalled actually. Switching rsync compression off did change it to around 20% though.
I'll give multiple instances of rsync a try. Thanks
 
Please also check for the memory statistics, maybe using top. If the ARC is pushed almost to non-existence, you will see these performance issues.
 
top

Code: 
(...)
Mem: 118M Active, 4155M Intact, 3110M Wired, 114M Cache, 1530M Buf, 33M Free
ARC: 843M Total, 21M MFU, 621M MRU, 19M Anon, 26M Header, 157M Other
(...)

Running 7 instances of rsync at the moment. Seems like running several rsync instances and turning compression (-z) off speeded up the process.
I don't have any exact numbers for comparison though.
 
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