Quoting "Tim Connors" <[email protected]> > Don't ever use more than 80% of your file system? Yeah, I know that's not > a very acceptable alternative.
The 80% is a bit of an "old time myth", I was running ZFS with higher usage under FreeBSD until I hit the "slowness". http://portrix-systems.de/blog/brost/oracle-databases-on-zfs/ [About Solaris] "zfs actually switches to a different algorithm to find free blocks at a certain level and that this level is configurable with metaslab_df_free_pct. Older releases switch at about 80% full and try to find the best fit for new data which slows things down even more." More about the tuning here: http://blogs.everycity.co.uk/alasdair/2010/07/zfs-runs-really-slowly-when-free-disk-usage-goes-above-80/ To be honest, I don't know exactly the FreeBSD threshold. At the moment, Nagios is giving me a warning at 80% and then I start thinking about remedies (without feeling too much pressure at this point). Under untuned other filesystems you have a 5% threshold, non-privileged users cannot write after that. For my server usage, I accepted that I need some RAM (I usually reserve 4GB for the ARC) and some "wasted" disk space. Given that both are cheap I don't bother. I accepted it because it makes my life much easier in many regards. It saves me time I would spend to fiddle around with other solutions. Weren't computer invented to save time and do the boring stuff for you? BTW: I don't use dedup. Firstly because I use cloning many times and after that: Well, that are changes unique to the ZFS in question. I have problems to come up with a scenario to use it. But I am pretty sure someone asked for it. Maybe someone running a big big server farm and distributing copies of many many Gigabytes of data to many VMs on the same box? Or something like that. I mean, not every feature needs to be used by me. And it's not on by default so it does not bother me. Regards Peter _______________________________________________ luv-main mailing list [email protected] http://lists.luv.asn.au/listinfo/luv-main
