[OpenIndiana-discuss] using a ssd

[Clement BRIZARD]

I got it from an ebay auction, 30 euros. I will see if it is used out 
when I will receive it.

Le 03/11/2013 21:35, Jim Klimov a écrit :
> On 2013-11-03 21:05, Clement BRIZARD wrote:
>> Hello everybody,
>> I just got , for very cheap, a 64go slc ssd, I thought about using it as
>> cache for my current zfs pool.
>>
>> The pool is used mainly over nfs.
>>
>> What do you think I should do with the ssd, l2arc, zil, both ? if both
>> what size of partition ?
>
>
> NFS is frequently linked with sync IO which can be boosted by a ZIL.
> However, a number of dtrace scripts as well as temporary setting of
> "sync=disable" on your working datasets (since you already have some
> load) can show whether your on-disk ZIL is actually used and so if
> its offload to SSD would actually help.
>
> Sizing depends on your write intensity, usual recommendations are to
> reserve 3 to 5 times your total HDD bandwidth over the ZFS TXG sync
> period (5 seconds nowadays by default). For most small machines this
> amounts to 4-8Gb devices being appropriate as a dedicated ZIL.
>
> The rest can be used as an L2ARC, though you might also want to first
> wipe the device (with low-level format if available, or at least fill
> with zeroes) and leave some empty space as a reserve for SSD garbage
> collection and redundancy. Its cheapness did not come out of nowhere?
> Is it somewhat used and worn-out already? ;)
>
> Good luck,
> //Jim
>
>
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