topic Re: VA7400 Performance. in Disk Enclosures

VA7400 Performance.

RAC_1 — Mon, 19 May 2003 01:50:55 GMT

Setup -

VA7400 connected to 4 nodes through fiber hub.

Array configured in 0+1 raid level. Latest firmware
updated(HP18) on array. SDM A.1.06.00.

I am trying to improve it's performance by setting
LUN accesss depending upon primary controller.

It should be such that the LUN from redudant group-1
will be accessed through it's primary controller.

Used armtopology command on the server where SDM is
installed, but how do figure out the primary
controller when LUN is allocated to other server.

As said earlier total four nodes access array through
two controllers. - for redudancy. I am having
difficulty deciding which is the primary controller
for each LUN.

Thanks in Advance.

Re: VA7400 Performance.

Khalid A. Al-Tayaran — Mon, 19 May 2003 04:37:04 GMT

Hi,

FYI:RAID 0+1 is also called auto RAID.

For your question, from your shell (as root user) type cvui

you get a menu to either exit or select one of your VAs.

select one of the VAs. Select option 2: Configuration and status. Our VA 7100 gave this:
Exec command: armdsp -s 50060b0000153035

Vendor ID:______________________________HP
Product ID:_____________________________A6188A
Array World Wide Name:__________________50060b0000153035
Array Serial Number:____________________00SG230J0161
Alias:__________________________________sky
-----------------------------------------------------------

SUB-SYSTEM SETTINGS

RAID Level:___________________________HPAutoRAID
Auto Format Drive:____________________On
Capacity Depletion Threshold:_________100%
Queue Full Threshold Maximum:_________4096
Enable Optimize Policy:_______________True
Enable Manual Override:_______________False
Manual Override Destination:__________False
Read Cache Disable:___________________False
Rebuild Priority:_____________________High
Security Enabled:_____________________False
Shutdown Completion:__________________0
Subsystem Type ID:____________________0
Unit Attention:_______________________True

I think this automatically configured by default.

I hope I gave you something useful.

Re: VA7400 Performance.

RAC_1 — Mon, 19 May 2003 05:39:10 GMT

Khalid,

There is a difference in Autoraid and in 0+1.

When armtopology command is executed it gives you primary controller for each LUN.

My problem is how to decide primary controller for other servers. (AS some LUNS are allocated to other servers also)

Thanks anyway.

Not getting enough responses for this query.

Re: VA7400 Performance.

RAC_1 — Mon, 19 May 2003 06:01:17 GMT

Pushing to the TOP, to get some response.

Gurus have a look at this.

Re: VA7400 Performance.

Kiran Kumar Aekabote — Mon, 19 May 2003 07:14:59 GMT

Hi Anil,

To see/assign the primary controller for each LUN. Run sam on the server, select disks and File systems under that select disk devices, will display all LUNs and disk devices. select the specific LUN and go to actions tab select disk array maintenance and click on view array status informatoin. From this move(press tab) to the controller from the menu and press enter. Displays whether the particular controller is assigned to the LUN.

Use armperf of the SDM to check performance of a specific LUN at a specific time period, for more info see the man page of armperf

Good Luck
Kiran

Re: VA7400 Performance.

Zeev Schultz — Mon, 19 May 2003 12:10:02 GMT

Some notes about performance paths in va7400:

Performance Path:

The ???performance path??? is the most direct path the host can take to the data in the array. It is specified by two separate device files that direct the data either through Controller 1 or through Controller 2. The performance path is always the faster path in terms of data transfer rate.With two array controllers, the host will always have two paths to the data:
??? The ???primary path??? is the most direct path through the primary controller, whose redundancy group owns the logical unit (LUN). In order to access the data, the host simply talks directly to that controller.
??? The ???secondary path??? is the indirect path through the secondary controller. In order to access the data, the host must talk to the secondary controller, which does not own the LUN. The secondary controller then uses the N-way bus to send data to the primary controller,whose redundancy group owns the LUN. Whenever the secondary path is used, there is a performance penalty associated with that operation.

The following example illustrates how the performance path is used in a VA 7400:
Suppose LUN 2 is owned by Redundancy Group 2 under Controller 2. An HP-UX host has two
device files that have two separate paths to LUN 2: The primary device file that addresses
Controller 2, and the secondary device file that addresses Controller 1. The performance path usesthe primary device file, since Controller 2 owns LUN 2. The non-performance path uses the secondary device file. If the secondary device file is used, the data flows through Controller 1,across the N-way bus to Controller 2, and out to LUN 2 and its associated disk drives.

zeev

Re: VA7400 Performance.

Eugeny Brychkov — Mon, 19 May 2003 13:51:42 GMT

I'm not sure that SAM will build up correct path order (placing primary controllers into primary path) and you will need to build VGs manually using command line (or rebuild previously built by SAM removing and adding alternate links).
Odd disks (D1, D3, ...) are within RG1 and owned by C1, even disks (D2, D4, ...) are within RG2 and owned by C2.
In addition to setting perfomance path I would suggest to 'balance' disks between RGs, let's say, if you have 32 disks better to have 16 disks in RG1 and 16 in RG2 than 24 in RG1 and 8 in RG2. Then, when you've 'balanced' disks between RGs, you can balance LUNs between RGs and thus VA controllers. Then build up a VGs with primary paths to appropriate VA controllers.
Most issue here with hpux is HOW to identify controllers and thus primary paths in ioscan. In your stiruation (private loop) it's very simple: look into 'armdsp -a' output and check VA controller's port-id (in host ports settings section). By default C1=108 and C2=110. Looking to ioscan you can see the field next to 8.0 will be this port-id
Eugeny

Re: VA7400 Performance.

Ian Hillier — Tue, 20 May 2003 16:51:56 GMT

If you can telnet into your hub or switch, you can print your name server information and figure it out from there. I have a Brocade switch and here's how it looks -

from ioscan:
0/4/0/0.1.18.39.0.0.1 /dev/dsk/c10t0d1
0/7/0/0.1.18.39.0.0.1 /dev/dsk/c6t0d1
0/4/0/0.1.19.42.0.0.1 /dev/dsk/c15t0d1
0/7/0/0.1.19.42.0.0.1 /dev/dsk/c8t0d1

0/4/0/0.1.18.39.0.1.1 /dev/dsk/c10t1d1
0/7/0/0.1.18.39.0.1.1 /dev/dsk/c6t1d1
0/4/0/0.1.19.42.0.1.1 /dev/dsk/c15t1d1
0/7/0/0.1.19.42.0.1.1 /dev/dsk/c8t1d1

from Brocade nsShow:
NL 011227; 3;50:06:0b:00:00:09:3a:49;50:06:0b:00:00:09:70:59; na
FC4s: FCP [HP A6188A HP18]
NL 01132a; 3;50:06:0b:00:00:09:3a:4b;50:06:0b:00:00:09:70:59; na
FC4s: FCP [HP A6188A HP18]

Reading ioscan, the 4 and 7 denote which slot the FC card is plugged in taken from the back of the server and the very last 1 is the LUN number from SDM (if you have more than 8 LUNs, this will increment to 1.0, 1.1 for LUNs 9, 10 and so on).
The only thing we're concerned with from nsShow is the second column or Pid. The last 2 numbers (27 and 2a) translated from hex are 39 and 42 and the number just before that (2 and 3) are the physical port numbers on the switch.

Hmm, I can't remember what the 18 and 19 are in the path but they somehow are determined from the first set of hex values in the third column of nsShow. Here I just followed the cable from port 2 in my switch and found it going to controller 1 on my VA7100. :|

SO, I see that the physical path for c10t0d1 is from the HBA in slot 0/4/0 to port 2 of my switch then onto controller 1 of my VA7100.

Since the 7100 only has 1 RG, it's not so important that every LUN use controller 1 for it's primary link (otherwise, how would C2 ever get used?) but on a 7400 you surely want to make the distinction. I use pvlinks so the above order would be the most effective for LUN 1 (IMHO).

Sorry for the long wind, hope some of it helps

Regards,
John

Re: VA7400 Performance.

Tobias Hartlieb — Wed, 21 May 2003 14:07:57 GMT

Hi,

One can try to figure this out from the different FC port WWN...
try this:

armdsp -c |grep -e 'Controller At' -e WWN -e Port
=> This gives you the Port WWN of both Controllers of VA

Then, on the attached hosts, do this:
(get td'X' from ioscan -fnk)
fcmsutil /dev/td'X' get remote all | grep -e Target -e Symbolic
=> this gives, which Port WWN (etc..) are connected to FC HBA td'X' ..
=> on comparison, you can see which Controller is connected to which host (if direct connect)
=> otherwise, check on FC Switch, e.g. 'nsshow' / 'switchshow' on Switch, etc.

Alternatively, I wrote a small script (attached file) - which surely needs some improvements - but maybe can be used as a start...
It relies on the output of "armdsp" for VA Ctl WWN and armtopology (Device Node WWN: cf. 'man armtopology'). Check in the output, if the Device Port WWN matches the ID of the Controller 'C', which is owner of the LUN. If yes, you are attached to the Primary/owning Controller, if not, you go via the alternate link...

Regards.

Tobias