[linux-lvm] Mounted, but idle LVM volume causes constant disk writes

[Bostjan Skufca]

Greg, spot on!

I did found it a bit weird that mkfs on 5tb volume was faster than usual
(well, I did notice I didn't notice inode tables counter being slow) :)
I have to check other hosts though.

Thank you!
b.



On 4 June 2013 12:59, Greg Zapp <greg.zapp at gmail.com> wrote:

> This is just a general stab, but has the filesystem been fully initialized
> on those?  The default for ext4 is to do a lazy initialization of the
> filesystem and journal when you create it.  Depending on the size of the
> file system this can last for some time.  To prevent this use:
> mkfs.ext4 -E lazy_itable_init=0,lazy_journal_init=0
>
> -Greg
>
>
> On Tue, Jun 4, 2013 at 5:46 PM, Bostjan Skufca <bostjan at a2o.si> wrote:
>
>> Hello,
>>
>> If LVM2 volume is mounted (ext4 fs), why is there constant write activity
>> to the devices below (sw raid in this case) despite not using the mounted
>> volume at all?
>>
>> I am seing this on multiple hosts. On this particular one I am seeing
>> around 20 writes per second on average, but they occur in batches of around
>> 50-90 writeIOps on every 3-4 seconds. If I mount the same filesystem (ext4)
>> on sw raid1 without LVM in between, I see the expected 0 write IOps when
>> not using the filesystem.
>>
>> Kernel versions where I noticed this: 3.0.13 (sysrescd) 3.4.1, 3.9.4
>> (custom compiled). I noticed it on all systems where lvm is in use.
>>
>> Thank you for the hints,
>> b.
>>
>>
>> PS: I did search the web first, but I could not find the answer. Sorry if
>> this has been answered before, maybe I was searching for the wrong terms.
>>
>>
>> _______________________________________________
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>> linux-lvm at redhat.com
>> https://www.redhat.com/mailman/listinfo/linux-lvm
>> read the LVM HOW-TO at http://tldp.org/HOWTO/LVM-HOWTO/
>>
>
>
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>
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