HPE Community read-only access December 15, 2018
This is a maintenance upgrade. You will be able to read articles and posts, but not post or reply.
Hours:
Dec 15, 4:00 am to 10:00 am UTC
Dec 14, 10:00 pm CST to Dec 15, 4:00 am CST
Dec 14, 8:00 pm PST to Dec 15, 2:00 am PST
cancel
Showing results for 
Search instead for 
Did you mean: 

luns

 
A.G.M. Velthof
Valued Contributor

luns

Hello to all,

we are planning a new Oracle cluster with storage on 2 Eva's, using hpux 11.31.
Per Oracle instance we need 80 GB storage.
Is there still any reason for us to create
4 x 20 GB from performance point of view or is it sufficient to create 1 x 80 GB.
6 REPLIES
Sachin Kumbla
Frequent Advisor

Re: luns

Hi

If you are using 4 luns to create a 80gb FS then the only advantage will be i/o on disks will be reduced if you use stripping while creating the LVM.

This will give a better performance.

Rgds.,
Sachin Kumbla
Johnson Punniyalingam
Honored Contributor

Re: luns

As post above by >>Sachin Kumbla <<

Oracle recommends the same "Logical volume to stripped while creating" for better performance,
Problems are common to all, but attitude makes the difference
Johnson Punniyalingam
Honored Contributor

Re: luns

Benefits of striping:

1) Increase the performance of applications that read and write large sequentially accessed files. Striping with randomly accessed files yields inconsistent performance.

2) If each of the disk has their own controller instead of using a common
controller, each can process and transmit data simultaneously, resulting in further performance gains.

3) You can use familiar, standard comands to manage your striped disks, i.e. lvcreate, diskinfo, newfs, fsck, mount, all work with striped disk.

Drawbacks of Striping:

1) Since disk striping uses multiple disks, there is a greater likelihood of disk failure for any one of them, thus requiring restoring from backup (if not mirrored).

2) More complexity occurs when some of the disks have both striped and non-striped logical volumes. It is recommended, but not required that all the logical volumes within the same volume group be striped.

3) Since it is recommended that all the logical volumes within the same volume group be striped, if one of the disks goes bad, then recovery of multiple filesystems may be needed.

4) Performance could actually decrease if your disks are on the same controller and the I/O for one disk has to wait for completion of I/O on another disk.


Other considerations:
----------------------
1) Best performance occurs from a striped logical volume that spans similar disks. The more closely you match the disks in terms of speed, capacity, and interface type, the better the performance. For example, when striping across several disks of varying speeds, performance will be no faster than the slowest disk.

2) If you have more than one interface card or bus to which you can connect the disks, distribute the disks as evenly as possible among them to achieve best I/O performance.
Problems are common to all, but attitude makes the difference
A.G.M. Velthof
Valued Contributor

Re: luns

Even if it is on a EVA? Is the performance advantage worth it to create 4 instead of 1?
Sachin Kumbla
Frequent Advisor

Re: luns

Hi

Yes Velthof I can very well understand your issue that an from EVA a chunk is presented instead of LUN.

It depends upon the usage & criticality of your organisation.

Rgds.,
Sachin Kumbla
A.G.M. Velthof
Valued Contributor

Re: luns

Ok, thank You both for the answers.

Greetings, Alfons