extremely slow file creation/deletion after xfs ran full

[Carsten Aulbert]

Hi Stan

On 01/13/2015 09:06 PM, Stan Hoeppner wrote:
> This workload seems more suited to a database than a filesystem. Though
> surely you've already considered such, and chose not to go that route.
> 

Yepp, but as we do not fully control the server software and need to
work further on the binary blobs arriving, a database is also not that
well suited for it, but yes, we looked into it (and run mysql, marida,
cassandra, mongo, postgresql, ...)

> With high fragmentation you get lots of seeking.  What model disks are
> these?  What is your RAID10 geometry?  Are your partitions properly
> aligned to that geometry, and to the drives (512n/512e)?

Disks are 2TB Hitachi SATA drives (Ultrastar, HUA722020ALA330). As these
are some yrs old, they are native 512byte ones. They are connected via
an Areca 1261ML controller with a Supermicro backplane.

RAID striping is not ideal (128kByte per member disk) and thus our xfs
layout is not ideal as well. Things we plan to change with the next
attempt ;)

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 :)

Cheers

Carsten