Configuring RAID 5 on Solaris 9 using SVM

[xc0de]

I have 6 disks and would like to configure a RAID 5 array using 5 disks and 1 Hotspare. I am alittle confused after browing the I-Net and looking in the Sun forums. Can one set-up RAID 5 on the root or boot disk after installing the OS? My impression is after installing Solaris on the boot or root disk you can create a RAID 5 array with the remaining disks left and you cant create the array on the root disk. Do you need to mirror the root and then create the RAID 5 with the remaining disks and then mount the slice.... Any information would be greatly appreciated.

 

[Willemvrm]

You can not put root, /usr and swap on a raid 5 volume. Also you can not put any existing filesystem on a raid 5 without doing a backup and restore as all data will be overwritten and you have to do a newfs after the metadevice has been created.

So, this is probably what you want:
1) install the os on disk 0
2) mirror /, /usr, swap and any other fs which can not be unmounted using disk 0 and 1
3) create a raid 5 for your data filesystems (which can than be devided into soft partitions, if needed) using disk 2, 3 and 4
4) define disk 5 as a hot spare, if you want a hot spare as the boot- and data disks are redundant although if a disk in raid 5 fails you will lose a lot on performance.

But check out docs.sun.com for the online SVM Admin Guide which will expain all the possebilities. And also shows how to set up you metadb's which needs to be done correctly to ensure your uptime when a boot disk fails.

 

[cndcadams]

Willemvrm;

I was wondering where you found the information that you could not create raid 5 on the root filesystem? I need to teach a class(my first one and this would actually be very good information.

Thanks

CA

 

[Willemvrm]

Sorry for the late reaction, just back from a vacation.

The info can be found in:
Solaris Volume Manager Administration Guide

http://docs.sun.com/app/docs/doc/817-5776/6ml784a4s?q=svm&a=view

Chapter 14 RAID 5 Volumes (Overview)
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Overview of RAID 5 Volumes
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> However, you cannot use a RAID 5 volume for root (/), /usr, and swap, or for > existing file systems.