[linux-lvm] Question about thin-pool/thin LV with stripes
zdenek.kabelac at gmail.com
Fri Jan 25 21:53:46 UTC 2019
Dne 24. 01. 19 v 16:06 Eric Ren napsal(a):
> With single command to create thin-pool, the metadata LV is not created
> with striped
> target. Is this designed on purpose, or just the command doesn't handle
> this case very
> well for now?
> My main concern here is, if the metadata LV use stripped target, can
> thin_check/thin_repair tools work fine?
> In our use scenario, we want to use DM thinp for a lot of containers as
> rootfs. The container use heavy on snapshots,
> so above 4K thin/snapshots LVs may share the thin pool concurrently.
> This may make the space fragmented. So, another concern is, will using striped
> thinp make
> fragmentation much more worse?
When 'stripe_size' is the 'right size' - striped device should appear faster,
but telling you what's the best size is some sort of 'black magic' :)
Basically - strip size should match boundaries of thin-pool chunk sizes.
i.e. for thin-pool with 128K chunksize - and 2 disks -
I'd assume best result you should get with 64K stripesize (so 2 disks will
make it 128K stripe) - but it depends on number of hw aspects.
So you will need to benchmark it.
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