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RAID-5 disk pool creation with AIX
attempting to create a RAID -5 in a pSeries 9131-52A server.
Have 4 - 146GB drives, one has AIX 5.3 m O.S. loaded on it.
Is it possible ( and reccomended ) to create a RAID-5 set with 3 drives and one hot spare ?
Thus the O.S. drive being part of the RAID set.
I have mirrored the O.S. before but have not put it into a RAID set.
What would be the proper steps involved ?
Thanks Randy
Have 4 - 146GB drives, one has AIX 5.3 m O.S. loaded on it.
Is it possible ( and reccomended ) to create a RAID-5 set with 3 drives and one hot spare ?
Thus the O.S. drive being part of the RAID set.
I have mirrored the O.S. before but have not put it into a RAID set.
What would be the proper steps involved ?
Thanks Randy
ASKER
I am using a 5703 Ultra320 SCSI RAID adapter,..it only supports 0, 5 , 10.
remembering that one of the drives is the O.S. boot device,...
Do I create an array candidate pdisk and format all drives to 522 byte sectors first?
Or do I create the RAID set first ?
When do I create the "hot spare"?
Thanks
Randy
remembering that one of the drives is the O.S. boot device,...
Do I create an array candidate pdisk and format all drives to 522 byte sectors first?
Or do I create the RAID set first ?
When do I create the "hot spare"?
Thanks
Randy
There is a nice document here that walks you through the process
http://support.bull.com/documentation/byproduct/servers/escala/platforms/escala-ctrl/g/86Y122EM00/86A122EM00.pdf/attachment_download/file
Look at pages 13,14.
Before you start, I would make sure you have latest firmware for the controllers and patches, and power cycle, then create a mksysb tape. Test this to, unless you have 100% confidence that all is well.
The PDF covers pdisk, building the array, formatting, and defining a hot spare. Pretty painless as it give examples
http://support.bull.com/documentation/byproduct/servers/escala/platforms/escala-ctrl/g/86Y122EM00/86A122EM00.pdf/attachment_download/file
Look at pages 13,14.
Before you start, I would make sure you have latest firmware for the controllers and patches, and power cycle, then create a mksysb tape. Test this to, unless you have 100% confidence that all is well.
The PDF covers pdisk, building the array, formatting, and defining a hot spare. Pretty painless as it give examples
ASKER
Excellent.
Do you foresee any issues with me using the boot drive with O.S. loaded on as part of the RAID set ?
Do you foresee any issues with me using the boot drive with O.S. loaded on as part of the RAID set ?
Hi,
having rootvg on a hardware RAID5 array has one big drawback - since AIX doesn't allow for growing disks in the rootvg
you will not be able to later add disks to that array in order to get more space. (Well, you can add them, but AIX will not see the additional space).
Anyway, if you really want to do it this way - do you plan to leave the OS intact, or are you goig to reinstall?
If you're going to reinstall, everything will be just straightforward.
Just boot from the diagnostic CD, set up the RAID using the tools contained on that CD
according to your needs and then install your OS on the resulting hdisk0 (which is the array in reality)
Keeping the OS intact means that you must use the fourth disk a spare disk since you can't add
data disks to the array (see above).
The steps for the latter method should be as follows (assuming rootvg is just hdisk0)
Use smitty "rm_ary_mgr_menu" for the following tasks
- change hdisk1, hdisk2 and hdisk3 to array candidates. This implies formatting the 522 byte sectors.
You will get pdisk0, pdisk1, pdisk2
- create a raid 5 array containing pdisk0, pdisk1 and pdisk2.
You will get a new hdisk1
Use " smitty lvm" for the following steps
- add hdisk1 to rootvg
- mirror the rootvg to hdisk1
- remove the mirror on hdisk0
- remove hdisk0 from rootvg
Use smitty "rm_ary_mgr_menu" for the following tasks
- change hdisk0 to an array candidate.
You will get pdisk3
- add this disk as a hot spare to your array
Please remember - adding pdisk3 as a data disk will have no effect (as seen from AIX).
And please remember, too, what I wrote above - you will not be able to increase the array by adding disks!
wmp
having rootvg on a hardware RAID5 array has one big drawback - since AIX doesn't allow for growing disks in the rootvg
you will not be able to later add disks to that array in order to get more space. (Well, you can add them, but AIX will not see the additional space).
Anyway, if you really want to do it this way - do you plan to leave the OS intact, or are you goig to reinstall?
If you're going to reinstall, everything will be just straightforward.
Just boot from the diagnostic CD, set up the RAID using the tools contained on that CD
according to your needs and then install your OS on the resulting hdisk0 (which is the array in reality)
Keeping the OS intact means that you must use the fourth disk a spare disk since you can't add
data disks to the array (see above).
The steps for the latter method should be as follows (assuming rootvg is just hdisk0)
Use smitty "rm_ary_mgr_menu" for the following tasks
- change hdisk1, hdisk2 and hdisk3 to array candidates. This implies formatting the 522 byte sectors.
You will get pdisk0, pdisk1, pdisk2
- create a raid 5 array containing pdisk0, pdisk1 and pdisk2.
You will get a new hdisk1
Use " smitty lvm" for the following steps
- add hdisk1 to rootvg
- mirror the rootvg to hdisk1
- remove the mirror on hdisk0
- remove hdisk0 from rootvg
Use smitty "rm_ary_mgr_menu" for the following tasks
- change hdisk0 to an array candidate.
You will get pdisk3
- add this disk as a hot spare to your array
Please remember - adding pdisk3 as a data disk will have no effect (as seen from AIX).
And please remember, too, what I wrote above - you will not be able to increase the array by adding disks!
wmp
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normally you install drivers with diag -a ant then configure with diag
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Thanks
In general, you just can do this via smit.