Re: extremely slow file creation/deletion after xfs ran full

Carsten Aulbert
2015-01-14T06:07:28Z

Hi Stan

On 01/13/2015 09:43 PM, Stan Hoeppner wrote:
> With your file sizes that seems a recipe for hotspots. What do the
> controller metrics tell you about IOs per drive, bytes per drive? Are
> they balanced?
>

They looked ok from 10000ft, but unfortunately, the controller is not
that talkative :(

>> After the arrival of "advanced format" HDD and SSDs we usually try to
>> align everything to full 1 MByte or larger, just to be sure any
>> combination of 512b, 4kb, ... will eventually align :)
>
> It's not that simple with striping. Partitions need to start and end on
> stripe boundaries, not simply multiples of 4KB or 1MB as with single
> disks. If you use non power of 2 drive counts in a stripe, aligning at
> multiples of 1MB will screw ya, e.g. 12 drives * 64KB is a 768KB stripe.

At the moment there are 16 disks (or 8 "data" disks), so here, power of
2 still prevails. But still, very valid remark!