ZFS vs OSX Time Machine

[Thomas Ronner]

Hi,

On 4/28/11 4:03 PM, Daniel O'Connor wrote:
> Does anyone else use ZFS to store TM backups?
>
> I find that whenever my laptop (over wifi!) starts a TM the ZFS machine it's backing up to grinds to a halt.. Other systems streaming stuff over NFS from it also tend to stall..

Are you using zfs compression? If so, try turning that off.

I have a pool with a couple of filesystems with gzip-9 compression 
enabled. Whenever I write (using zfs receive, it is a backup server) to 
one of those volumes the whole pool stalls with lots of disk activity. 
Even creating a  snapshot on another filesystem within the same pool 
lasts a couple of minutes.

Does anyone know how to make this perform a little better? It's only 
writing small amounts (70-100 ops/s, 1 MB/s) on an otherwise idle pool. 
Still the drive leds blink like crazy. One of my two CPU cores is maxed 
out, the other is idle. I suppose it won't get any faster (it's CPU 
bound because of the heavy gzip compression), but why is the pool so 
slow? Is zfs receive using synchonous writes?

Sorry for maybe being offtopic :-)



Regards,
Thomas