Striping in AutoRaid

[Fabrizio Fiorito]

Hi all,
I'd like to know if is possible to set striping on 4 disk into a SureStore E Disk Array 12H.
I'd like to create one volume group with 4 physical volume (4 disks)and some logical volume into this volume group.
Logical Volumes will be in striping on all 4 disks and i like insets this config in autoraid configuration.
Is it possible ?
Tahnks in advance,
Fabrizio Fiorito

[CHRIS_ANORUO]

It is not advisable for you to use stripping on a raid subsystem.

Check this link for more information
http://www.hp.com/cposupport/prodhome/hpsurestor19162.html

[Andreas Voss]

Hi,

LVM striping is the best way to
use both AutoRaid controllers
simultaneously. With out
striping, LVM fills up the
physical volumes (LUNs)
sequentially so even if you
created a Volume Group of more
than one physical volume (LUN),
it would only use one controller

until the first physical Volume
was full. LVM striping requires
at least 3 Physical Volumes
(LUNs). So, if you only had one
AutoRaid you would want to
divide
it into 3 or 4 equal size LUNs.
With 2 AutoRaids, you would want

to stripe across physical
volumes
(LUNs) on both AutoRaids so you
would be using all 4 controllers

simultaneously. Thus 2 LUNs on
each AutoRaid would be
sufficient.
(This is an extract of a thread
at the 'Mass Storage' forums)

Regards

[Stefan Farrelly]

I dont understand Chris's reply. We use striping on Raid devices all the time and the performance increase is wonderful. As far as im concerned stripe your lvols over as many controllers and disks as possible, the more the merrier (and faster).

[unixdaddy]

The following link states that on HP SureStore E Disk Array Models 12/12H "Data is automatically distributed across the disks in the array to optimize performance. No user intervention is required to keep data balanced". So based on this there should be no need to strip, whether this is true or not remains to be seen. I for one would like a definate answer.

http://www.hp.com/cposupport/information_storage/support_doc/lpg75004.html

[Ramesh Donti]

Hi,
I agree with Darren that, striping is not required just incase of Autoraid 12H because it itself balances I/O across all disks. For better load balancing from system point of view, while creating volume group, use Physical volumes of different SCSI channels.

Long back, we did a performance analysis using striped and non-striped logical volumes. We didn't find any performance improvement by using striping.

[Ramesh Donti]

Hi,
I agree with Darren that, striping is not required just incase of Autoraid 12H because it itself balances I/O across all disks. For better load balancing from system point of view, while creating volume group, use Physical volumes of different SCSI channels.

Long back, we did a performance analysis using striped and non-striped logical volumes. We didn't find any performance improvement by using striping.

[Ramesh Donti]

Hi,
I agree with Darren that, striping is not required just incase of Autoraid 12H because it itself balances I/O across all disks. For better load balancing from system point of view, while creating volume group, use Physical volumes of different SCSI channels.

Long back, we did a performance analysis using striped and non-striped logical volumes. We didn't find any performance improvement by using striping.

[Fabrizio Fiorito]

Hi all,
just a clarification.
On our customer has a SureStore E DiskArray 12H connected to a HP9000 L2000.
He contacted us because he reported several performance problems using our software.
I checked the situation using GlancePlus.
Result : disks in autoraid are the bottleneck.
I was sure of this, because using raid0+1 or raid5 or raid1 (with striping setted) the our sw works very fast.
So, question is if i can set stripe and later I can set autoraid on it
Thanbks again,
Fabrizio

[Andreas Voss]

Hi,

for performance information of AutoRAID i would prefer you to look at:
http://www.hp.com/cposupport/information_storage/support_doc/lpg75003.html

and
http://www.hp.com/cposupport/information_storage/support_doc/lpg75007.html

Regards