Troubleshooting Backup issues

Backing up files can be troublesome. Speeds can reach disasterous new lows, and files tend to get corrupted along the way. It might just seem like more trouble than it’s worth, but in our experience, it makes the difference of hours and days. However, with the correct tools and information, it is possible to narrow down the problem, and even solve it. Below is a troubleshooting guide for common reasons why your server backup process may be causing errors.

1.Here is a summary of what we will be examining in order to better realize a potential problem:

oDocument any noticeable problems

oWhen did you notice the change or error(s)?

oHave there been any changes to the main backup server, media servers, or backup clients?

oWhat, if anything, have you done already to troubleshoot this problem?

oDo you have any site documentation?

oWhat are your expectations once the problem has been ratified

2.Hardware Related Slow-down

oThe speed of the disk controller and hardware errors caused by the disk drive, tape drive, disk controller, SCSI bus, or even improper cabling/termination can slow performance.

oTape drives are incompatible with SCSI Raid Controllers.

oFragmented disks (act of data being written on different physical locations of a disk) take much longer to back up. Not only will it affect the rate at which data is written, but it will affect your overall system performance. A solution to this is simply by defragmentation.

oThe amount of available memory greatly impacts backup speed. A lack of free hard disk space is a commonly overlooked issue. This is generally due to improper file paging settings.

3.File Types and Compression

oThe average file can potentially compress at a 2:1 ratio if hardware compression is used. Backup speed could potentially double if average compression is used prior.

oThe total number of files on a disk, and the relative size of each file is important in calculating backup speed. The fewer large files, the faster the backup.

oBlock size has an important role in compression, and thus, affects backup speed. The bigger the block size, the more capable the drive is to achieve better throughput and increased capacity. It is not recommended to increase the Block Size above the default.

4.Remote-Disk Backup

oThe backup speed for a remote disk is limited by the speed of the physical connection. The rate at which a remote server’s hard disks are able to be backed up depends on the make/model of network cards, the mode/frame type configuration for the adapter, the connectivity equipment (hubs, switches, routers, and so on), and the Windows NT 4 or Windows 2000 settings.

oA commonly overlooked reason for slowdown on network backups can be the configuration of the network itself. Certain features such as “Full-Duplex” and “Auto-Detect” may not be fully supported in every environment. Setting the speed to 100Mb and duplex to half/full on the server side, and 100 MB on the switch port is the common practice. Dependent on the resulting speeds, half or full duplex will be the better solution.

5.Methods to potentially improve tape backup performance

oMake sure the tape drive is properly defined for the host system. It is common for a SCSI host to disable the adaptive cache on the drive if it is not recognized. The cache enables features like drive streaming to operate at peak performance.

oPut the tape drive on a non-Raid controller by itself.

oMake sure all settings in the controller’s Post Bios Setup Utility are correct.

oMake sure the proper driver updates have been applied for the SCSI Controllers.

oConfirm proper cabling/termination for the devices being used.

oUpdate the firmware on the tape drive to the latest level. In some cases, the firmware may actually require downgrading to improve performance.

oCheck the tape drive and tape media statistics to see if errors occur when backups run.

oCheck the Windows NT or Windows 2000 Application Event Logs for warnings/errors.