Additional Solstice DiskSuite Topics


Creating Transaction Logging Metadevices

DiskSuite provides the capability to do file system logging for UFS file systems. Logging enables a quicker and cleaner startup of disk partitions following a crash or irregular shutdown. Changes made to the filesystem are kept in a log which is then reapplied to the filesystem during a disk checking procedure. Using logging devices helps to ensure both data integrity as well as quicker startup times. DiskSuite logging devices are known as metatrans devices.

A metatrans device is identical to any other kind of meta device. In order to configure the device it is assumed that there is a free slice on each disk. Logging devices should be approximately 1MB in size for each 100MB of file system space that will be logged. Creating logging devices greater than 64MB, however, is usually a waste of disk space.

Using our previous example setup, lets assume that slice 3 of each disk is not being used for a metadb. Again, creating the metatrans mirror is identical to creating any other kind of mirror. 

# metainit d13 1 1 c0t0d0s3
# metainit d23 1 1 c0t1d0s3
# metainit d3 -m d13
# metattach d3 d23
Remember, it is necessary to reboot after creating the individual submirrors and before attaching them using metaattach.

Next, we will actually configure our partitions to utilize the new logging devices. In this example we are going to add transaction logging to our /export and /var file systems. 

# metainit -f d64 -t d4 d3
# metainit -f d67 -t d7 d3
Warning: According to the DiskSuite documentation, the root (/) file system cannot utilize metatrans devices.

In addition, any 'system' file system, such as /usr, /var, etc. must have logging disabled before any kind of Solaris upgrade or installation.

Finally, we must udpate /etc/vfstab to point to the new meta devices for /var and /export, as in the following example: 

/dev/md/dsk/d64  /dev/md/rdsk/d64 /var    ufs     1       yes    -
/dev/md/dsk/d67  /dev/md/rdsk/d67 /export ufs     1       yes    -
After the vfstab file is updated, it is necessary to reboot the system in order to begin using the new devices.


Creating RAID 5 Devices

Creating a RAID 5 metadevice with DiskSuite is extremely simple. Unlike creating mirrors which involves several steps, creating a RAID 5 device consists of running a single command. If hot spare disks are desired, the hot spare pool must have been previously created. Refer to the following example of creating a hot spare pool and a RAID 5 device: 

# metainit hsp001 c2t2d0s0 c3t2d0s0 c1t2d0s0
# metainit d30 -r c1t1d0s0 c2t0d0s0 c2t1d0s0 c2t3d0s0 c3t1d0s0 -i 64k -h hsp001
The -r signifies that this will be a RAID 5 device. Next are the list of slices which will be part of the RAID 5 device. The -i option specifies the interleave size to be used, in this case, we are using 64 Kbytes. Finally, -h specifies the hot spare pool to be used with this metadevice.


Other Useful DiskSuite Tasks

Creating a striped metadevice: 

# metainit d10 1 2 c0t1d0s2 c0t2d0s2 -i 32k
Creating a concatenation of 2 slices: 
# metainit d25 2 1 c0t1d0s2 1 c0t2d0s2
Creating a concatenation of 4 slices: 
# metainit d25 4 1 c0t1d0s2 1 c0t2d0s2 1 c0t3d0s2 1 c0t4d0s2


More Information

The definitive source of information on Solstice DiskSuite is Sun Microsystem's documentation. The following three volumes comprise the DiskSuite documentation set:

These documents, and much more, can be browsed online or downloaded as pdf files at http://docs.sun.com.

Another excellent reference is Jeannie Kobert's Guide to High Availability: Configuring boot/root/swap, part of Sun's new Blueprints series of books. This book uses a cookbook approach to setting up high availability configurations using both DiskSuite and Veritas Volume Manager. While background information and theory is missing from this work, if you need to quickly get a server mirrored using DiskSuite or Volume Manager, this book will walk you through it, step by step.