[CentOS-virt] Xen vs. iSCSI

Tue Jun 16 03:33:28 UTC 2009
Luke S Crawford <lsc at prgmr.com>

Bill McGonigle <bill at bfccomputing.com> writes:
> In the DomU, I'll see a lock-up, and then filesystem errors.  e.g.:
> 
>    Installing     : kernel [############################################ 
> ]  1/33EXT3-fs error (device xvda1) in ext3_ordered_writepage: IO failure
> 
> In the Dom0, I'll see:
> 
>    sd 6:0:0:0: timing out command, waited 360s
>    sd 6:0:0:0: SCSI error: return code = 0x06050000
>    end_request: I/O error, dev sdc, sector 37319



try 

xm sched-credit -d 0 60000

and see if you still have the problem.

if that doesn't work, try

xm vcpu-set 0 1

then edit all your domu config files and add:
cpus="1-7"

(assuming a dual socket quad core box... the idea is to reserve a cpu
for the dom0)  



the idea is that if your dom0 is starved for CPU, you get all sorts of
network and other I/O weirdness.