Member Avatar for blur0224

Hi all,

I'm designing a system that will use Solaris 10/9 with a RAID 0 + 1 configuration.

My guess is that if I install the system using one disk with partitioning, I'll be able to setup the RAID 0 + 1 configuration from command line. If the installation is all on one disk, when I setup RAID 0 for the additional disks, it will need to stripe the install across all the disks, which doesn't make sense because it would have to overwrite where it's reading from. I feel as though the RAID setup should be completed in BOIS prior to installation, but all of the tutorial/books indicate that the configuration is done after the installation.

Once I have one set of disks stripped, I'll stripe the other set then mirror the two sets.

Any advice would be greatly appreciated.

Thanks!

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Short answer: either build the array in your RAID controller before you install (the OS then sees one logical disk), or install to a single disk and convert the root to a striped-and-mirrored metadevice with Solaris Volume Manager (SVM). was right to point out that using multiple partitions on a single physical disk gives no redundancy — that won’t help for fault tolerance. Hardware RAID is the simplest for root installs because the controller hides the physical layout and presents a single bootable disk. Example vendor docs showing controller-created logical drives and virtual-drive tools.. (cisco.com)

If you prefer software RAID with Solaris Volume Manager you can convert an existing install into a RAID-0 submirror and then mirror it; the supported sequence is: create the first concat/stripe from the mounted root slice with metainit -f, create the second concat on the other disk, create the mirror with metainit -m, run metaroot (so the system knows to boot from the metadevice), reboot, then metattach the second submirror to start resync. Also install bootblocks on the alternate disk and verify your BIOS can boot from it. Example commands (platform paths vary):

# metainit -f d11 1 1 c0t0d0s0
# metainit -f d12 1 1 c0t1d0s0
# metainit d10 -m d11
# metaroot d10
# lockfs -fa
# reboot
# metattach d10 d12
# installboot /usr/platform/`uname -i`/lib/fs/ufs/pboot /usr/platform/`uname -i`/lib/fs/ufs/bootblk /dev/rdsk/c1t1d0s2

Follow the Oracle SVM mirror/root procedure exactly (do not attach the second submirror before the reboot step, and watch out for the separate x86 boot partition on x86 systems). Solaris Volume Manager mirror/root instructions and cautions.. (docs.oracle.com)

One more note on topology: “RAID 0+1” (mirror of stripes) and “RAID 1+0 / RAID10” (stripe of mirrors) behave differently under multiple failures; RAID10 is generally preferred for rebuild speed and fault tolerance if you can arrange mirrored pairs first. If you’re planning 8 disks on a single controller, creating the nested array in the controller (or using controller-supported RAID10) is often the cleanest for boot and performance; still keep backups — striping (RAID0) by itself offers no redundancy. RAID10 vs RAID0+1 explainer. (thegeekstuff.com)

(References above provide the exact SVM commands and cautions to follow if you go the software route.)

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Member Avatar for rch1231

I don't believe what you are describing is possible with just one hard drive. You are attempting to use partitions for the RAID instead of physical disks. RAID, an acronym for Redundant Array of Independent Disks (Changed from its original term Redundant Array of Inexpensive Disks), is a technology that provides increased storage functions and reliability through redundancy. This is achieved by combining multiple disk drive components into a logical unit, where data is distributed across the drives in one of several ways called "RAID levels".

You would actually run slower attempting to access multiple partitions on the same drive as opposed to accessing data across multiple physical drives. The following site may give you a better idea of what RAID is and how it is used:

http://en.wikipedia.org/wiki/RAID

Member Avatar for blur0224

I need to clarify what I want to do. Forget about the partitioning for now, that's a non-issue.

I want to install Solaris 10/9 on 2 (or possibly 4) stripped hard disks, RAID 0. The issue is that RAID 0 is setup after Solaris is installed, according to all the tutorials, books, and documentation. Unless there is something I'm missing, this is impossible unless RAID 0 is setup prior to the installation.

Supposing there are two disks not stripped. Solaris is installed on one of them. Then Solaris is configured with RAID 0 for both disks. This doesn't seem possible because it would have to read from the same disk that it's writing too, i.e. the information it would have to read would be overwritten prior to being read.

I've come to the conclusion that RAID 0 will need to be configured in the BIOS prior to installation, however, I'm unable to find anything that verifies this.

Member Avatar for rch1231

What you want is a RAID controller card to connect the drives to. You will setup the RAID on the drives prior to installing the OS and the OS will see the array without any problems as a single install drive.

Member Avatar for blur0224

Supposing I used a RAID controller for 4 disks, should I use another one for the other 4? After installation, I can do this through Solaris, but it seems like I should be consistent.

Member Avatar for blur0224

I just realized that if I setup all 8 disks with a single controller, I can configure the controller to use a RAID 0 + 1 configuration.

Thanks for your help!

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