ASM I/O size
in [Oracle]
|
Prev: Fresh Enterprise Manager Install Can't connect "Connection Closed"
Next: SELECTing from a DML statement
From: maks71 on 3 Jul 2008 17:25 Hello, I'm running under 10.2 database on AIX5.3L I have disk group ASM_DATA which has 100 SAN equi-sized (256GB) disks/ luns. with MBRC of 16 & Block size of 16K , When I read a table of 10GB via FTS, what should be my I/O size/lun ? Should my I/O size be same for all the LUNs? 1) ASM level 2) I/O stats (iostat -D ) Thanks
From: K Gopalakrishnan on 7 Jul 2008 00:17 ASM uses (by default) 1MB as the stripe size. It is called Allocation Unit (AU) in ASM terminology. This ASM AU size is (crudely) like your extent size for datafiles and ASM reads one extent at a time from a disk. Depending on how many disks you have you read n*1MB data per read. There is an 'asmiostat' in the 11g version and I am not aware of any such thing in your version. -Gopal On Jul 3, 4:25 pm, mak...(a)gmail.com wrote: > Hello, > I'm running under 10.2 database on AIX5.3L > > I have disk group ASM_DATA which has 100 SAN equi-sized (256GB) disks/ > luns. with MBRC of 16 & Block size of 16K , When I read a table of > 10GB via FTS, what should be my I/O size/lun ? Should my I/O size be > same for all the LUNs? > > 1) ASM level > 2) I/O stats (iostat -D ) > > Thanks
From: maks71 on 7 Jul 2008 12:11
Gopal Thanks for your response.. few Questions reg. your following comment... >Depending on how many disks you have you read n*1MB data per > read. There is an 'asmiostat' in the 11g version and I am not aware > of any such thing in your version. > So in my example of reading 10GB table on 100x256GB ASM disk group, Will oracle issue 100MB/Read? Will it not take into account formula max(MBRC* DB Block size, Max size supported by AIX )? I don't see 1MB/Read in my iostat -D reading. I see more or less ~200KB/Read and Just wondering why.. Thanks |