Analyst: Keys To Surviving A Disaster

Preston, who addressed storage end users during the Storage World Conference here Monday, said the first step to making it through a disaster is to define what is an acceptable loss of data. This requires putting a monetary value on the loss of each part of a company's data against the measured cost of a data backup system.

The second step is to make sure all data is backed up, said Preston. It is very common for companies to set up a list of data that should be backed up, instead of making a list of data that should be excluded, he said.

The backup list must include backup catalogs for database files, Preston said. "If you have a database tracking all your tapes, guess which database is your most important," he said. "That one. %85 Recovery of your backup catalog should be the easiest recovery and the most tested recovery you have."

Preston also said it is important to back up the operating system. "Smaller shops, and some larger shops, say they don't want to back up the operating system because it never changes," he said. "But over time, it takes such a small part of the backup, it's not worth excluding it."

There are several different technologies an enterprise can use as part of its backup program, said Preston. The one that has the most potential to change the way backups are done at the enterprise level is the increasing use of ATA drive-based Fibre Channel arrays as part of a disaster-recovery and high-availability program, he said.

"ATA-based Fibre Channel has brought the cost [of data replication over multiple sites] down to nothing," he said. "So now you can do asynchronous replication to another site."

Preston said disk-to-disk to tape backups, in which data is first backed up to an inexpensive remote disk array and then to a tape library, make sense for users looking to back up incremental data changes on a continual basis. It is also useful for consolidating backups. "One client with 100 sites was doing local backups to tape," he said. "Instead, they can replicate data from those sites to a central site or a co-location facility, and then back that data up to tape. . . . This is not new. But it is becoming popular because the prices [for the arrays] are way down."

Small businesses are very similar to enterprises in that they must know the value of their data, which systems they can live without for a period of time, and which systems are absolutely critical to their company, said Preston. For the very small businesses, sometimes the loss of a single hard drive can mean the end of the company, he said.

For companies with less than 10 servers, Preston said it is best to use disk arrays instead of tape for backups. He said to back up 100 Gbytes of data to tape requires the purchase of an AIT or similar drive with media for around $2,500, compared with about $200 for a 100-Gbyte hard drive or $1,600 for a new computer with 1 Tbyte of capacity.

Just as important, he said, small businesses typically lack experienced IT personnel. "The No. 1 problem with truly small businesses is they don't manage their media," he said. "They don't take the tapes out of the drives, or replace tapes when they are ejected."

One solution small businesses should consider is using laptop backup software for their desktops and servers, with data from those desktops or servers backed up to a server in a co-location facility.

The laptop backup software has the advantage in that it can be set up to perform backups automatically, as opposed to the typical small business where people do not regularly back up, said Preston.

Instead of a co-location service, a small business may also consider having a DSL line installed to the owner's home and then back up company data to a server placed there, said Preston.

One end-user attendee said the analyst makes a lot of sense, especially the tip to consider using disk arrays for backups.

Amir Sadeghi, senior database administrator for the Data Warehousing Group of Universal Music Group, Universal City, Calif., said his company, which uses a mixture of IBM, EMC and Hewlett-Packard storage devices, has a problem with the backup window for its batch data, and is considering using a disk array to help eliminate that window.

"Our backup window is about three hours now," Sadeghi said. "But because of a huge data warehouse we are building, that window time will spike this year. So we decided to dump the data to disk, and from there dump it to tape."

Sadeghi admitted that he does not know the potential cost of having his system go down. "I only know we can't afford to be offline," he said. "We have pretty demanding users."