[one-users] (thanks) Re: experiences with distributed FS?

[Hans-Joachim Ehlers]

Just a few remarks on performance: ( All imho )

1) Do not use any kind of asynchronies write. In case of a serious problem your data might not contains what you expecting.
2) If possible use Jumbo frames. To handle 100K interrupts (1500 bytes ) or 10k (9000 bytes) interrupts on a 1GbE links makes for a CPU and network adapter quite a difference
3) Sine any data goes down to disk - the disk subsystem will determine your overall speed. Use SDD for IOPS intensive application.*

*
a) 4 x 2TB SATA disk can handle about 4 * 100 IOPS which makes 400 IOPS. In case of 4 K writes your total reachable write speed would be 1.6 MB/s. Now think what happen if a VM starts swapping.
b) Slow disk systems can not be made faster on higher software stacks except in case where you do not care about your data ( async writes for example )

@ Michael ( xtremFS )
AFAIK uses GPFS VirtFS (v9fs). Maybe its an option for xtremFS as well.
I found on scribd (sic) http://www.scribd.com/darkcompanion/d/54839002-xVI05-Open-Source-Virtualization-With-KVM some information about GPFS /KVM and VIRTIO. Maybe usefull for you as well.


Have a nice weekend
Hajo