[linux-lvm] lvextend does not change/fix stripes & stripesize for the whole LV?
peljasz at yahoo.co.uk
Mon Mar 6 10:56:49 UTC 2017
On 06/03/17 09:47, Zdenek Kabelac wrote:
> Dne 4.3.2017 v 14:58 lejeczek napsal(a):
>> Or it does?
>> From man pages my understanding is - it does not, an
>> expression "the
>> extension" is used there.
>> If I have a LV with 2 stripes and 64KiB stripesizes, then
>> adding two more
>> stripes, like this:
>> $ lvextend h300Int1/0 -i 2 -I 16 /dev/sd3 /dev/sd4 (if it
>> was to succeed)
>> will change the LV into 4 stripes LV, but what would
>> happened to stripesize(s)?
> At this moment lvm2 supports extension only of the same
> So extended/added segment will have some 'geometry' as the
> last/previous segment of your extended LV.
> So if you do not add any 'striping' parameters - they will
> be automatically detected from LV, if you add them - they
> will be compared and in case of mismatch operation will be
> Also if the allocation policy and free space in VG allows
> - extension will try first to extend existing segment
> before allocating new space somewhere else in VG.
may I share a comment - inasmuch as man pages for lvm are
really good, there are places where some bits are missing.
Take LVEXTEND, it speaks of --alloc but does not elaborate
on it at all.
--use-policies Resizes the logical volume
according to configured policy. See lvm.conf
But I failed to find it there in lvm.conf.
Would be great to have man pages completed with these
missing bits. It's rhel 7.3, lvm2-2.02.166-1.el7_3.2.x86_64
Ca I also ask you - reason I'm hoping I could downsize the
stripesize is for I understand that with higher number of
stripes stripesize could shrink so data(smaller files) would
go to more(all?) stripes(increasing transfers speeds, phy
devs are all SSDs in my case). Is my logic false here?
And if it is not, would then creating a second LV(the same
VG) with different(smaller) stripesize, then moving data
over there, then removing the first LV and finally extending
that "second" LV be a good, a correct way?
> linux-lvm mailing list
> linux-lvm at redhat.com
> read the LVM HOW-TO at http://tldp.org/HOWTO/LVM-HOWTO/
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