RAID chunk size configuration from kickstart

Kovacs, Corey J. cjk at techma.com
Thu Dec 23 07:00:49 UTC 2010 

My guess is that it's usually a setting used based on a known metric of I/O load. Only when you know exactly what the average load for the particular set of disks is for a particular usage pattern, can you begin define what the chunk size is. 

Experimentation is of course the only real way to find the right value but once you do, and you combine that with the stride settings for the file system you lay on top of the raid it will help.

That all said, I guess it'd be nice to have as an option since one might have a known set of systems already doing the same thing.

Anyway, good luck.

-C
________________________________________
From: kickstart-list-bounces at redhat.com [kickstart-list-bounces at redhat.com] on behalf of Jay Naikwadi [jnaikwadi at asterdata.com]
Sent: Wednesday, December 22, 2010 7:23 PM
To: kickstart-list at redhat.com
Subject: RE: RAID chunk size configuration from kickstart

>>Just curious, why do you need an 8M chunk size? What sort of devices are you writing to?
>>-C

Well the box is normal dell C2100 box with (LSI MegaRAID SAS 9260-8i w/ 512 MB cache 12x 450GB, 15K SAS).
I am playing with different RAID configuration to see what numbers I get for pure block I/O performance.
But looks like I will have to get this done in %post section.

Just wondering though why does not kickstart allow setting chunk size directly if underlying utilities support this parameter ?

-Jay

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> Subject:
> Re: RHEL 6 Anaconda Error - AttributeError
> From:
> Chris Lumens <clumens at redhat.com>
> Date:
> Tue, 21 Dec 2010 09:15:19 -0800
> To:
> "kickstart-list at redhat.com" <kickstart-list at redhat.com>
>
> To:
> "kickstart-list at redhat.com" <kickstart-list at redhat.com>
>
>
>
>> Here's a link to the anaconda-tb-* ...
>>
>> http://www.aqr.aero/files/anaconda-tb-tTx5Tj
>
> Hm, that wasn't very enlightening.  This is one of those bugs where a
> lot of people should be hitting it, but this is the first I have heard
> of it.  Can you think of anything unusual you did during install?  Did
> you run media check?  Is it at all reproducible?
>
> - Chris
>
>
>
> ------------------------------------------------------------------------
>
> Subject:
> RE: RAID chunk size configuration from kickstart
> From:
> Jay Naikwadi <jnaikwadi at asterdata.com>
> Date:
> Tue, 21 Dec 2010 11:47:37 -0800
> To:
> "kickstart-list at redhat.com" <kickstart-list at redhat.com>
>
> To:
> "kickstart-list at redhat.com" <kickstart-list at redhat.com>
>
>
>
> Well in my case the nodes did have exact same config so that is not issue.
> But if kickstart command itself supported additional parameters it would
> have been lot simpler to specify chunk size. As in other cases we need
> to worry about different devices names(sd*/cciss*) etc and do all of
> this stuff in %post section to set the chunk size.
>
> But just to confirm , so there is no way this can be done using
> kickstart 'raid' command and has to be done using tools like mdadm in
> %pre / %post sections ?
>
> Thanks,
> Jay
>
> kickstart-list-request at redhat.com wrote:
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>> ------------------------------------------------------------------------
>>
>> Subject:
>> RE: RAID chunk size configuration from kickstart
>> From:
>> "Kovacs, Corey J." <cjk at techma.com>
>> Date:
>> Fri, 17 Dec 2010 23:04:28 -0800
>> To:
>> Discussion list about Kickstart <kickstart-list at redhat.com>
>>
>> To:
>> Discussion list about Kickstart <kickstart-list at redhat.com>
>>
>>
>>
>>
>>
>>
>>
>>
>> As far as I know, not for the root fs which "normally" shouldn't be a
>> problem since setting the chunk size is a performance tuning task and
>> you typically don't do high load tasks against your root fs (Well I
>> don't anyway). So, I'd suggest simply building a small root fs using
>> the normal kick start methods, then elsewhere in your post section,
>> manually create the raid device and file-system where you need to set
>> the chunk size. Also, this is sort of predicated by all of your nodes
>> are exactly the same and have exactly the same (or very similar)
>> workload. -C
>> ------------------------------------------------------------------------
>> *From:* kickstart-list-bounces at redhat.com
>> [kickstart-list-bounces at redhat.com] on behalf of Jay Naikwadi
>> [jnaikwadi at asterdata.com] *Sent:* Wednesday, December 15, 2010 2:10 PM
>> *To:* kickstart-list at redhat.com *Subject:* Re: RAID chunk size
>> configuration from kickstart
>> Jay Naikwadi wrote:
>>> Hi , I am trying to deploy software raid setup using  kickstart and
>>> was wondering if I can specify chunk-size as parameter in kickstart
>>> file.I am using RHEL 6.  I didn't see any documentation for this
>>> parameter in kickstart. The default installation seems to be using
>>> 512K as chunk size whereas I would like to set it to 8MB . This is
>>> new device configuration and there is nothing configured on system
>>> before this. If kickstart does not allow setting this parameter ,  Is
>>> there another way in %pre , %post sections where we can change it ?
>>>  How else this parameter could be set for  '/' ,  '/boot/'
>>>  partitions  on clean install ? Thanks and regards, Jay
>> Any suggestions about how this could be done ? -Jay
>>
>>
>
>
>
> ------------------------------------------------------------------------
>
> Subject:
> RE: RAID chunk size configuration from kickstart
> From:
> "Kovacs, Corey J." <cjk at techma.com>
> Date:
> Tue, 21 Dec 2010 12:16:02 -0800
> To:
> Discussion list about Kickstart <kickstart-list at redhat.com>
>
> To:
> Discussion list about Kickstart <kickstart-list at redhat.com>
>
>
>
> Just curious, why do you need an 8M chunk size? What sort of devices are you writing to?
>
> -C
> ________________________________________
> From: kickstart-list-bounces at redhat.com [kickstart-list-bounces at redhat.com] on behalf of Jay Naikwadi [jnaikwadi at asterdata.com]
> Sent: Tuesday, December 21, 2010 2:47 PM
> To: kickstart-list at redhat.com
> Subject: RE: RAID chunk size configuration from kickstart
>
> Well in my case the nodes did have exact same config so that is not issue.
> But if kickstart command itself supported additional parameters it would
> have been lot simpler to specify chunk size. As in other cases we need
> to worry about different devices names(sd*/cciss*) etc and do all of
> this stuff in %post section to set the chunk size.
>
> But just to confirm , so there is no way this can be done using
> kickstart 'raid' command and has to be done using tools like mdadm in
> %pre / %post sections ?
>
> Thanks,
> Jay
>
> kickstart-list-request at redhat.com wrote:
>> Send Kickstart-list mailing list submissions to
>>       kickstart-list at redhat.com
>>
>> To subscribe or unsubscribe via the World Wide Web, visit
>>       https://www.redhat.com/mailman/listinfo/kickstart-list
>> or, via email, send a message with subject or body 'help' to
>>       kickstart-list-request at redhat.com
>>
>> You can reach the person managing the list at
>>       kickstart-list-owner at redhat.com
>>
>> When replying, please edit your Subject line so it is more specific
>> than "Re: Contents of Kickstart-list digest..."
>>
>> ------------------------------------------------------------------------
>>
>> Subject:
>> RE: RAID chunk size configuration from kickstart
>> From:
>> "Kovacs, Corey J." <cjk at techma.com>
>> Date:
>> Fri, 17 Dec 2010 23:04:28 -0800
>> To:
>> Discussion list about Kickstart <kickstart-list at redhat.com>
>>
>> To:
>> Discussion list about Kickstart <kickstart-list at redhat.com>
>>
>>
>>
>>
>>
>>
>>
>>
>> As far as I know, not for the root fs which "normally" shouldn't be a
>> problem since setting the chunk size is a performance tuning task and
>> you typically don't do high load tasks against your root fs (Well I
>> don't anyway). So, I'd suggest simply building a small root fs using
>> the normal kick start methods, then elsewhere in your post section,
>> manually create the raid device and file-system where you need to set
>> the chunk size. Also, this is sort of predicated by all of your nodes
>> are exactly the same and have exactly the same (or very similar)
>> workload. -C
>> ------------------------------------------------------------------------
>> *From:* kickstart-list-bounces at redhat.com
>> [kickstart-list-bounces at redhat.com] on behalf of Jay Naikwadi
>> [jnaikwadi at asterdata.com] *Sent:* Wednesday, December 15, 2010 2:10 PM
>> *To:* kickstart-list at redhat.com *Subject:* Re: RAID chunk size
>> configuration from kickstart
>> Jay Naikwadi wrote:
>>> Hi , I am trying to deploy software raid setup using  kickstart and
>>> was wondering if I can specify chunk-size as parameter in kickstart
>>> file.I am using RHEL 6.  I didn't see any documentation for this
>>> parameter in kickstart. The default installation seems to be using
>>> 512K as chunk size whereas I would like to set it to 8MB . This is
>>> new device configuration and there is nothing configured on system
>>> before this. If kickstart does not allow setting this parameter ,  Is
>>> there another way in %pre , %post sections where we can change it ?
>>>  How else this parameter could be set for  '/' ,  '/boot/'
>>>  partitions  on clean install ? Thanks and regards, Jay
>> Any suggestions about how this could be done ? -Jay
>>
>>
>
> _______________________________________________
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>
>
> ------------------------------------------------------------------------
>
> Subject:
> RE: RHEL 6 Anaconda Error - AttributeError
> From:
> "Speagle, Andy" <andy.speagle at wichita.edu>
> Date:
> Wed, 22 Dec 2010 08:09:57 -0800
> To:
> Discussion list about Kickstart <kickstart-list at redhat.com>
>
> To:
> Discussion list about Kickstart <kickstart-list at redhat.com>
>
>
>
>>> Here's a link to the anaconda-tb-* ...
>>>
>>> http://www.aqr.aero/files/anaconda-tb-tTx5Tj
>> Hm, that wasn't very enlightening.  This is one of those bugs where a lot
>> of people should be hitting it, but this is the first I have heard of it.
>> Can you think of anything unusual you did during install?  Did you run
>> media check?  Is it at all reproducible?
>
> Well, keep in mind this is a kickstart generated via Spacewalk v1.2 ... I cloned the majority of it from a RHEL 5 kickstart.  I'm not certain if there are new directives I need to be considering.  Here's the relevant generated kickstart...  Perhaps there's something you can readily identify.
>
> # Kickstart config file generated by Spacewalk Config Management
> # Profile Label : rhel-x86_64-server-6-0
> # Date Created  : 2010-11-29 21:27:30.0
>
> install
> text
> network --device=eth0 --bootproto=dhcp --noipv6
> url --url http://spacewalk.wichita.edu/ks/dist/rhel-x86_64-server-6-0
> lang en_US
> keyboard us
> zerombr yes
> clearpart --all --drives=sda --initlabel
> bootloader --location mbr --driveorder=sda --append="rhgb quiet"
> timezone --utc America/Chicago
> auth --enablemd5 --enableshadow
> rootpw --iscrypted <nunya>
> selinux --disabled
> reboot
> firewall --enabled --port=22:tcp
> skipx
> firstboot --disabled
> part /boot --fstype ext4 --size=200 --ondisk=sda
> part pv.6 --size=100 --grow --ondisk=sda
> volgroup rootvg --pesize=32768 pv.6
> logvol swap --fstype=swap --name=swap --vgname=rootvg --size=2048
> logvol /var --fstype=ext4 --name=var --vgname=rootvg --size=2048
> logvol /var/tmp --fstype=ext4 --name=vartmp --vgname=rootvg --size=1024
> logvol /home --fstype=ext4 --name=home --vgname=rootvg --size=2048
> logvol /tmp --fstype=ext4 --name=tmp --vgname=rootvg --size=1024
> logvol /opt --fstype=ext4 --name=opt --vgname=rootvg --size=2048
> logvol / --fstype=ext4 --name=root --vgname=rootvg --size=4096
>
> %packages
> @core
> @base
> @java
> lvm2
> gcc
> gcc-c++
> net-snmp
> sysstat
> strace
> ntp
> screen
> compat-libstdc++-33
> -NetworkManager*
> -bluez*
> -yum-updatesd
> %end
>
>
> Thanks,
>
> Andy
>
>

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