ZFS vs OSX Time Machine

[Daniel O'Connor]

On 29/04/2011, at 11:43, Artem Belevich wrote:

> On Thu, Apr 28, 2011 at 6:08 PM, Jeremy Chadwick
> <freebsd at jdc.parodius.com> wrote:
>> I will note something, however: your ARC max is set to 3072MB, yet Wired
>> is around 4143MB.  Do you have something running on this box that takes
>> up a lot of RAM?  mysqld, etc..?  I'm trying to account for the "extra
>> gigabyte" in Wired.  "top -o res" might help here, but we'd need to see
>> the process list.
>> 
>> I'm thinking something else on your machine is also taking up Wired,
>> because your arcstats shows:
>> 
>>> kstat.zfs.misc.arcstats.c: 3221225472
>>> kstat.zfs.misc.arcstats.c_min: 402653184
>>> kstat.zfs.misc.arcstats.c_max: 3221225472
>>> kstat.zfs.misc.arcstats.size: 3221162968
>> 
>> Which is about 3072MB (there is always some degree of variance).
> 
> The difference is probably due to fragmentation (most of ARC
> allocations are served from power-of-2 zones, if I'm not mistaken) + a
> lot of wired memory sits in slab allocator caches (FREE column in
> vmstat -z). On a system with ARC size of ~16G I regularly see ~22GB
> wired. Ona smaller box I get about 7GB wired at around 5.5GB ARC size.

This system also does double duty as a desktop PC so it gets a fair hammering..

It did have 4GB of RAM but that was fairly terrible, 8GB is a lot better though :)

--
Daniel O'Connor software and network engineer
for Genesis Software - http://www.gsoft.com.au
"The nice thing about standards is that there
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