Re: Performance considerations of a disk hosting lpar Was: Disk: Percent full a performance factor?

Just saw this after my previous note. We've not seen it be a factor if the host partition is truly just that. NOTHING FRIGGIN ELSE in there. Not an FTP host not running any workload. In fact you can have the system in restricted condition and the guest partitions roll on.

Gone to 95% full and not seen an issue.

Now Some Say that the hosted disk should all be in it's on ASP. Done that too AND it allows PowerHA to mirror entire systems. (VERY cool by the way) This way you can be assured that no other I/O is in those pools and that no fragmentation is occuring as nothing whatever is moving on those disks.

- Larry "DrFranken" Bolhuis

www.frankeni.com
www.iDevCloud.com
www.iInTheCloud.com

On 10/20/2014 3:46 PM, rob@xxxxxxxxx wrote:

On a loosely related note, what performance considerations should one
really watch for on an lpar that does nothing but host disk? For example
on our Power 8's all disk (except to the vios lpars) is hosted by one lpar
of IBM i. This then hosts several lpars of IBM i and AIX.

RACK1HST: Hosts main production lpars
% CPU used . . . . . . . : 66.1
Auxiliary storage:
System ASP . . . . . . : 23277 G
% system ASP used . . : 54.3132
System Pool Reserved Max -----DB----- ---Non-DB---
Pool Size (M) Size (M) Active Fault Pages Fault Pages
1 896.18 369.86 +++++ .0 .0 1.9 1.9
2 6329.73 14.27 145 .2 1.4 6.3 30757
3 811.89 .00 203 .0 .0 .6 2.3
4 81.18 .00 5 .0 .0 .0 .0
Work with Disk Status
Elapsed time: 00:00:37
%
Busy
0
0
0
...
For all 32 SSD units.
Virtual Processors Processing units Memory
(GB)
Minimum Assigned Maximum Minimum Assigned Maximum
Minimum Assigned Maximum
RACK1HST 1 10 20 0.1 0.5 1 4 8
16


RACK2HST: Hosts Mimix lpars and backup Domino lpars.
% CPU used . . . . . . . : 5.1
Auxiliary storage:
System ASP . . . . . . : 22500 G
% system ASP used . . : 64.2344
System Pool Reserved Max -----DB----- ---Non-DB---
Pool Size (M) Size (M) Active Fault Pages Fault Pages
1 781.05 362.50 +++++ .0 .0 3.6 3.6
2 6444.86 14.21 175 .0 .0 5.8 255.6
3 811.89 .00 203 .0 .0 1.5 6.4
4 81.18 .00 5 .0 .0 .0 .0
Work with Disk Status
Elapsed time: 00:00:39
%
Busy
0
0
0
...
For all 30 SSD units.
Virtual Processors Processing units Memory
(GB)
Minimum Assigned Maximum Minimum Assigned Maximum
Minimum Assigned Maximum
RACK2HST 1 10 20 0.1 0.5 1 4 8
12


RACK3HST: Hosts rarely used test lpar and a triple backup of our Domino
lpars.
% CPU used . . . . . . . : 19.7
Auxiliary storage:
System ASP . . . . . . : 5956 G
% system ASP used . . : 45.8444
System Pool Reserved Max -----DB----- ---Non-DB---
Pool Size (M) Size (M) Active Fault Pages Fault Pages
1 691.21 352.51 +++++ .0 .0 .0 .0
2 6534.69 13.31 175 .0 .0 2.0 286.7
3 811.89 .00 203 .0 .0 1.2 8.1
4 81.18 .00 5 .0 .0 .0 .0
Work with Disk Status
Elapsed time: 00:00:29
%
Busy
0
0
0
...
for all 22 spinning disks.
Virtual Processors Processing units Memory
(GB)
Minimum Assigned Maximum Minimum Assigned Maximum
Minimum Assigned Maximum
RACK3HST 1 10 20 0.1 0.5 1 6 8
12



Rob Berendt