[linux-lvm] Question about thin-pool/thin LV with stripes
zkabelac at redhat.com
Fri Jan 25 21:47:19 UTC 2019
Dne 24. 01. 19 v 15:54 Eric Ren napsal(a):
> As you can see, only "mythinpool_tdata" LV has 2 stripes. Is that OK?
> If I want to benefit performance from stripes, will it works for me? Or,
> should I create dataLV, metadata LV, thinpool and thin LV using
> step-by-step way
> and specify "--stripes 2" in every steps?
> With single command to create thin-pool, the metadata LV is not created with
> target. Is this designed on purpose, or just the command doesn't handle this
> case very
> well for now?
Yes this on purpose currently.
When you create 'thin-pool' - you are mostly specifying options for 'DATA'
volume. The allocation of metadata is using 'internals' to pick the place
and other properties - we can maybe introduce some policy option
to make metadata raid1 or striped or something like that.
ATM it's not so easy to do the best possible allocation - so
for skilled admin - it's always most 'secure' to build pool
from bricks - data LV + meta LV.
The automatic allocation will get enhanced over the time - but it's
always somewhere 'fuzzy' what is going to be the results.
Basically - what is 'unspecified' on command line and left for lvm2 to figure
out - may change between releases - if we consider there is better solution.
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