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Storage August 2006 Special Supplement
|Helpful storage performance tools|
2) Streamline backups.
Backups can drain storage, network, server and staff resources. The best way to cut down on backups is to back up only the data that needs to be protected. Use the Windows search or Unix find commands to identify old, unaltered data. Work with management to understand the requirements of your recovery point objective. If your backup product has a full backup option, you may be able to do full backups less frequently and back up only the changed data daily.
Backup storage choices vary widely, from portable USB-interface 250GB to 500GB (Serial ATA) disk drives to large-capacity automated tape and virtual tape libraries. Make sure you understand your business requirements and size your backup systems accordingly. SATA can be used effectively for backups and is less expensive than its Fibre Channel (FC) and SCSI counterparts. Configured properly, SATA will perform very well for disk-to-disk backups or as a disk buffer pool before data is moved to tape. If you opt for SATA for your disk buffer pool, verify that the disks' read performance is high enough to keep the tape drives spinning--stop-and-start cycles on tape drives can dramatically decrease backup performance.
Many CAS systems use a checksum technology to determine if a block or stream of data resides on the system; if the data is already there, it won't keep any of the subsequent copies. This enables you to use less storage and reduce network bandwidth requirements if you're backing up data to a CAS system at a remote site. The efficiency of these systems will depend on your data. The one downside to using CAS systems today is that they're all proprietary.
There are many things to take into consideration with your backup server. Don't overlook using an x86-based backup server instead of a more expensive RISC system. If you're using an x86 backup server with Windows (Windows 2003 is preferred for its performance), matching input and output bandwidth will make the most efficient use of the backup server. Use test tools like Qcheck (network performance test), Iometer (disk IO performance test for Windows) or IOzone (disk IO performance for Unix and Windows) to get a performance baseline and to ensure that your system is performing at its rated throughput (see "Helpful storage performance tools," this page). If the throughput doesn't match the rated speeds, check your operating system parameters. If you're running Gigabit Ethernet, consider using jumbo packets to improve performance.
This was first published in August 2006