[olug] IO Performance

[Aric]

......He is consulting the list

Maybe ask if IBM has a tweak guide for their product.  I got a nice guide
for tweaking read ahead, queue depth, etc. from 3ware when I was in a
somewhat similar situation. 

https://www.3ware.com/3warekb/article.aspx?id=15244

https://www.3ware.com/3warekb/article.aspx?id=11050

I just looked at how big my average reads were to get a start and played
with it until I got it dialed in.

-----Original Message-----
From: olug-bounces at olug.org [mailto:olug-bounces at olug.org] On Behalf Of jay
swackhamer
Sent: Friday, September 16, 2011 5:50 AM
To: Omaha Linux User Group
Subject: Re: [olug] IO Performance

Bring in a consultant? I should probably let someone else work on my cars
too, huh.

I wasn't looking for someone to tune my environment, just looking to start a
thread of others experiences.......if you don't have any, I can research
cold as well as anyone else.......

I have a generic corporate environment.
Redhat/ext3/oracle/multipath/fibre channel SAN/service guard/30
databases/largest = 3+ tb, all random IO On Sep 15, 2011 10:06 PM, "Kevin"
<sharpestmarble at gmail.com> wrote:
> We'll need to know a lot more about the file access patterns, file 
> sizes, file systems, underlying hardware, and a whole lot of etcetera 
> to be able to answer this one. You might think of bringing in a 
> consultant for this. Specifically where you'd find such a consultant, 
> though, I don't know.
>
> On Thu, Sep 15, 2011 at 10:25, jay swackhamer 
> <reboottheuser at gmail.com>
wrote:
>> I know there are, but I was looking for some specifics, if anyone had 
>> an experience tuning, and what, if anything had a noticable impact.
>>
>> On Thu, Sep 15, 2011 at 10:09 AM, George Neill <georgen at neillnet.com>
wrote:
>>
>>> Jay,
>>>
>>> The file system you choose and the way you disk is laid out can have 
>>> a huge impact as well.
>>>
>>> There are many file system tunables you cam mess around with.
>>>
>>> Later
>>> George
>>>
>>> On 9/15/11, jay swackhamer <reboottheuser at gmail.com> wrote:
>>> > It appears that a code-level on the IBM XIV disk array that 
>>> > relates to replication has more to do with IO performance than Linux
Tuning.
>>> >
>>> > Now we are running batch schedules through Oracle faster than
previously,
>>> so
>>> > there was some benefit, and now I can tweak/tune these some more, 
>>> > to get to the best numbers for the workload.
>>> >
>>> > On the road to this discovery, I found these parameters related to 
>>> > IO performance.
>>> >
>>> > Does anyone else have any IO related tuning tips?
>>> >
>>> > echo 10 > /proc/sys/vm/swappiness
>>> > echo 1024 > /proc/sys/vm/min_free_kbytes sysctl -w vm.pagecache="1 
>>> > 10 30"
>>> > echo 192 > /sys/module/qla2xxx/parameters/ql2xmaxqdepth
>>> > multipath -ll > /tmp/multipath.txt for i in `grep sd 
>>> > /tmp/multipath.txt | awk ' { print $3 } '` do
>>> >     echo 192 > /sys/block/$i/device/queue_depth
>>> >     echo 384 > /sys/block/$i/queue/nr_requests
>>> >     echo 512 > /sys/block/$i/queue/read_ahead_kb
>>> >     echo deadline > /sys/block/$i/queue/scheduler done
>>> >
>>> > for i in `mount | grep vg | awk ' { print $1 } '` do
>>> >     mount -o remount,noatime,async $i done 
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