Re: Using Smalling LUNs for striping ASM disks with 3-Par Storage

> Does anyone know if we just request more LUNs that this will allow oracle to 'stripe' and spread out IO? Someone I work with is claiming it does and
> that Oracle told him to do this.

If the I/O is striped on storage level depends on how it is configured. We can not answer this. However LUNs are logical and could be placed in one storage array or placed over several storage arrays. This also depends on how it is configured on storage level.

Oracle stripes the I/O over several ASM disks per DG by default (it may makes no sense, if all LUNs / ASM disks are placed in the same storage array), but you can define how it should be done: http://docs.oracle.com/database/121/OSTMG/GUID-114A8CA6-D757-4A70-9F68-C5133724D7BB.htm

However only one large LUN per DG is not a good idea in general as you also have to consider the (SCSI) disk queue depth.

Best Regards
Stefan Koehler

Freelance Oracle performance consultant and researcher Homepage: http://www.soocs.de
Twitter: _at_OracleSK

> Dba DBA <oracledbaquestions_at_gmail.com> hat am 23. Februar 2016 um 17:50 geschrieben:
>
> I am in a large shop, so the SAN engineers are a completely different team. Getting time to talk to them is difficult. I have worked with SAN
> engineers in the past that have told me the following.
>
> LUNs are logical. Displaying more LUNs does not by itself represent spreading out IO since unless you map the LUNs to different RAID Groups and
> across the back plane (I think is what it was called) the IO will not be spread out. Last year I was told by one of our senior SAN Engineers that
> 3-Par storage does not out of the box offer spreadng out IO and we don't offer it. We would have to use a different type of way to allocate storage.
> This is a big hosting company so there are 10s of thousands of servers that are on SANs.
>
> Does anyone know if we just request more LUNs that this will allow oracle to 'stripe' and spread out IO? Someone I work with is claiming it does
> and that Oracle told him to do this.
>
> I think that having multiple LUNs isn't really different from having windows partition your hard drive and then you stripe over the C:\ and D:\
> drive.
>
 

--
http://www.freelists.org/webpage/oracle-l