Importing a vdev copied zpool from file
mike tancsa
mike at sentex.net
Thu Mar 26 14:17:34 UTC 2020
On 3/26/2020 10:07 AM, Gary Palmer wrote:
> What if you add the step
>> mdconfig *-o async*??-t vnode -f /data/da0
>>
>> and then try the import ? Note, the async option adds a pretty big speed
>> increase
> At least on 11.3, that option has this caveat in the man page:
>
> -o [no]option
> Set or reset options.
>
> [no]async
> For vnode backed devices: avoid IO_SYNC for increased
> performance but at the risk of deadlocking the entire
> kernel.
>
> Not sure if the risk of deadlocking the kernel is still there or if it's
> worth any potential speedup
Its quite a difference in speed. I have been using it for a while on
RELENG_12 without any deadlocks while virtualizing servers. On large
imports, it would give close to a 50% speedup
---Mike
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