Mark,

Sorry about the delay

On Mon, Jan 11, 2010 at 08:39:47AM -0500, Mark Johnson wrote:
> 
> 
> [email protected] wrote:
> >We have 2 sets of identical hardware, identically configured, both 
> >exhibiting disk i/o performance problems with 2 of their 4 DomUs
> >
> >The DomUs in question each act as a nfs filesever. The fileserver is 
> >made up from 2 zvols, one holds the DomU (solaris 10) and the other is 
> >mounted to the DomU and contains the user's files which are then nfs 
> >exported. Both zvols are formatted as UFS. For the first 25-30 nfs 
> >clients performance is OK, after that client performance drops off 
> >rapidly e.g. a "ls -l" of the user's home area taking 90 seconds. 
> >Everything is stock - no tuning.
> 
> When does xentop report for the guest? For both dom0 and dom0,
> what does iostat -x report?

During "normal" running the stats are

xentop:
      NAME  STATE   CPU(sec) CPU(%)     MEM(k) MEM(%)  MAXMEM(k) MAXMEM(%)
VCPUS NETS NETTX(k) NETRX(k) VBDS   VBD_OO   VBD_RD   VBD_WR 
SSID
  achilles -----r       2412  120.1    1580792   18.8    1581056      18.8
2    1   161632     8712    4        0      682     1006 
   0
  Domain-0 -----r      90049  164.1    2097152   25.0   no limit       n/a
2    0        0        0    0        0        0        0 
   0

Dom0 iostat:
device    r/s    w/s   kr/s   kw/s wait actv  svc_t  %w  %b 
sd0       0.0    0.0    0.0    0.0  0.0  0.0    0.0   0   0 
sd1       0.0    0.0    0.0    0.0  0.0  0.0    0.0   0   0 
sd2     486.7    0.0 4713.3    0.0  0.0  0.9    2.0   1  79 

DomU iostat:
device    r/s    w/s   kr/s   kw/s wait actv  svc_t  %w  %b 
cmdk0     0.0    0.0    0.0    0.0  0.0  0.0    0.0   0   0 
cmdk1   126.5  331.7 2593.7 3324.2  0.0  7.5   16.4   1  89 
cmdk2     0.0    0.0    0.0    0.0  0.0  0.0    0.0   0   0 


When performance drops off we get

xentop:
      NAME  STATE   CPU(sec) CPU(%)     MEM(k) MEM(%)  MAXMEM(k) MAXMEM(%)
VCPUS NETS NETTX(k) NETRX(k) VBDS   VBD_OO   VBD_RD   VBD_WR 
SSID
  achilles --b---       2475    0.6    1580792   18.8    1581056      18.8
2    1        0        0    4        0        0       14 
   0
  Domain-0 -----r      90140    7.1    2097152   25.0   no limit       n/a
2    0        0        0    0        0        0        0 
   0

Dom0 iostat:
device    r/s    w/s   kr/s   kw/s wait actv  svc_t  %w  %b 
sd0       0.0    0.0    0.0    0.0  0.0  0.0    0.0   0   0 
sd1       0.0    0.0    0.0    0.0  0.0  0.0    0.0   0   0 
sd2      39.7  161.3 2199.0 5919.7  0.0 17.7   88.2   0 100 

DomU iostat:
device    r/s    w/s   kr/s   kw/s wait actv  svc_t  %w  %b 
cmdk0     0.0    0.0    0.0    0.0  0.0  0.0    0.0   0   0 
cmdk1     1.3    1.0   26.7    4.0  5.7 32.0 16164.7 100 100 
cmdk2     0.0    0.0    0.0    0.0  0.0  0.0    0.0   0   0  

istats persist like this for 4 or 5 seconds and then drop back towards
"normal" but performance on the client remains very poor.

Thanks

John


> What Solaris 10 update?
> 
> Have you tried a PV opensolaris guest for the NFS server
> running the latest bits?  If not, can you do this? There
> have been some xnf (NIC driver) fixes which could explain
> this.
> 
> 
> 
> >Anyone any suggestions what I can do to improve matters - would using 
> >ZFS rather than UFS for the user disk change matters?
> 
> 
> It should not.
> 
> 
> 
> >The underlying disks are managed by a hardware RAID controller so the 
> >zpool in the Dom0 just sees a single disk.
> 
> Why wouldn't you use the disks as a jbod and give them all to
> zfs?
> 

-- 
John Landamore

Department of Computer Science
University of Leicester
University Road, LEICESTER, LE1 7RH
[email protected]
Phone: +44 (0)116 2523410       Fax: +44 (0)116 2523604

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