Re: SAN and Performance

I have had sum success with SETOBJACC in specific environments. Thing is
that if a particular object truly gets bashed thoroughly and enough memory
exists the object will likely be all or mostly all in memory already. If
enough memory does not exist then pulling the object into memory will hurt
other processes.

Bottom line is to know what you are doing! :-)

- Larry "DrFranken" Bolhuis

www.Frankeni.com
www.iDevCloud.com - Personal Development IBM i timeshare service.
www.iInTheCloud.com - Commercial IBM i Cloud Hosting.

On 11/24/2017 8:13 PM, Steinmetz, Paul wrote:

I had an interesting discussion with the MPG folks recently.
Question was
Can performance be improved over 100% SSD?
The answer is yes.
Put everything in memory, which is becoming more of a reality as memory
prices keep coming down.
It's an interesting concept.
Makes sense.
Remember years ago, before SSD drives were available, if you needed to
boost I/O performance, SETOBJACC.

The Set Object Access (SETOBJACC) command temporarily changes the
speed of access to an object by bringing the object into a main
storage pool or purging it from all main storage pools. An object
can be kept main storage resident by selecting a pool for the object
that has available space and does not have jobs associated with it.
Repeated use of the command can cause a set of objects to be
resident in a main storage pool.

The I/O would only be from the CPU to memory, virtually eliminating the
I/O.

Any thoughts from the group?

Paul

-----Original Message-----
From: MIDRANGE-L [mailto:midrange-l-bounces@xxxxxxxxxxxx] On Behalf Of
Steinmetz, Paul
Sent: Friday, November 24, 2017 3:40 PM
To: 'Midrange Systems Technical Discussion'; 'Gad Miron'
Subject: RE: SAN and Performance

From the performance folks at MPG.

Strictly from a performance standpoint, internal SSD using the top PCIe3
RAID Adapter will absolutely always outperform a SAN.

Paul

-----Original Message-----
From: MIDRANGE-L [mailto:midrange-l-bounces@xxxxxxxxxxxx] On Behalf Of
Steinmetz, Paul
Sent: Friday, November 24, 2017 9:15 AM
To: 'Midrange Systems Technical Discussion'; 'Gad Miron'
Subject: RE: SAN and Performance

1) How do determine what model SAN is needed?
https://www.ibm.com/storage/disk

2) Do all SANs offer the same performance?

3) How do you determine which attachment method should be used.
https://www-03.ibm.com/support/techdocs/atsmastr.nsf/5cb5ed7
06d254a8186256c71006d2e0a/fe962d4c9cefdcfc8625785600479c87/$
FILE/iExternalStorageMatrix_v170301.pdf

3) The SAN can be direct attached without using VIOS, correct?

4) Strictly from a performance standpoint, can a SAN outperform internal
SSD using the top PCIe3 RAID Adapter?

Our P7 8205-E6C is performing well with 100% SSD drives.
EOL was announced, so planning our next upgrade.
Power9 maybe a game changer.

Paul


-----Original Message-----
From: MIDRANGE-L [mailto:midrange-l-bounces@xxxxxxxxxxxx] On Behalf Of
DrFranken
Sent: Thursday, November 23, 2017 8:52 PM
To: Midrange Systems Technical Discussion; Gad Miron
Subject: Re: SAN and Performance

See Jim's response. The answer of course is "It Depends" but of course
properly designed it will match or exceed internal disk performance.
Poorly designed, notsomuch.

- Larry "DrFranken" Bolhuis

www.Frankeni.com
www.iDevCloud.com - Personal Development IBM i timeshare service.
www.iInTheCloud.com - Commercial IBM i Cloud Hosting.

On 11/22/2017 11:56 PM, Gad Miron wrote:

Hi Larry

Considering a new machine configuration...

Will SAN upgrade / degrade performance of Write-intensive applications ?
(Compared to 7TB internal disks?)

TIA
Gad

date: Wed, 22 Nov 2017 16:01:15 -0500
from: DrFranken <midrange@xxxxxxxxxxxx>
subject: Re: i hosting i question

Sure VIO can do that but SAN better choice.
You get things like easy tier to move hot data to SSD and cold data
away.

You get flash copy for doing backups at a point in time that's not
stuck while you are doing the backups.

You can add drawers on the fly unlike internal disk. There are also
more disk options with SAN as well.

I do NOT hate internal disk, reliable and predictable for decades but
SAN disk brings options that internal doesn't.

18TB, I'd be on SAN for sure.


- Larry "DrFranken" Bolhuis

www.Frankeni.com
www.iDevCloud.com - Personal Development IBM i timeshare service.
www.iInTheCloud.com - Commercial IBM i Cloud Hosting.


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