ZFS, Zvol, iSCSI and windows and mostly readonly

[Willem Jan Withagen]

On 26-9-2015 21:03, Willem Jan Withagen wrote:
> On 25-9-2015 16:05, Tom Curry wrote:
>> On Fri, Sep 25, 2015 at 7:13 AM, Karli Sjöberg <karli.sjoberg at slu.se
>> <mailto:karli.sjoberg at slu.se>> wrote:
>>
>>      fre 2015-09-25 klockan 11:08 +0200 skrev Willem Jan Withagen:
>>      > Hi,
>>      >
>>      > Because of the Network Video Recorder (on windows) we use only likes
>>      > "real" disks, and not SMB disks. We started using ZVOLs which are
>>      > exported thru iSCSI/ctld....
>>      >
>>      > And that works really well, so there all thumbs up for this combo.

Since this data is mainly write-only, and only to be read when old data 
needs to be reviewed. Which is hardly ever....

Do I, can I do, or should I do,  something about that data going into 
ARC or cache?
zfsraid/nvr  primarycache          all                    default
zfsraid/nvr  secondarycache        all                    default

With that I mean it only needs to go to disk, until it is deleted about 
30 days later, in the time in between the data is not accessed.

Now I have the idea that it goes into ARC and puts presure on memory 
that could be used for other things?

--WjW