Solaris Volume Manager Configuration Guidelines

A poorly designed Solaris Volume Manager configuration can degrade performance. This section offers tips for achieving good performance from Solaris Volume Manager.

General Guidelines

• Disk and controllers–Place drives in a volume on separate drive paths. For SCSI drives, this means separate host adapters. Spreading the I/O load over several controllers improves volume performance and availability.

• System files–Never edit or remove the /etc/lvm/mddb.cf or /etc/lvm/md.cf files.

  Make sure these files are backed up on a regular basis.

• Volume Integrity–After a slice is defined as a volume and activated, do not use it for any other purpose.

• Maximum volumes–The maximum number of volumes supported in a disk set is 8192 (though the default number of volumes is 128). To increase the number of default volumes, edit the /kernel/drv/md.conf file. See System Files and Startup Files for more information on this file.

• Information about disks and partitions–Have a copy of output from the prtvtoc and metastat -p command in case you need to reformat a bad disk or re-create your Solaris Volume Manager configuration.

File System Guidelines

• Do not mount file systems on a volume's underlying slice. If a slice is used for a volume of any kind, you must not mount that slice as a file system. If possible, unmount any physical device that you intend to use as a volume before you activate it. For example, if you create a transactional volume for a UFS, in the /etc/vfstab file, you would specify the transactional volume name as the device to mount and fsck.