HP StoreEver MSL2024, MSL4048, MSL8048, and MSL8096 Tape Libraries User and Service Guide (AK378-96059, December 2012)

NOTE: Processor speed numbers as based on Intel x86 type processors. Use the equivalent on
a RISC or other type of processor.
Table 37 Backup server requirements
Processor power/driveMinimum RAM/driveTape drive
2 GHz1 GBLTO-4 HH
3 GHz2 GBLTO-4 FH
4 GHz2 GBLTO-5, LTO-6
In addition to having enough RAM and processing power, ensure that the PCIe bus is at least 64
bit, has a speed of 66 MHz or better, and is not overloaded by too many high-bandwidth cards.
PCIe is preferred.
Backup type
Each type of backup has its own impact on performance, depending on how well it can keep data
streaming to the tape drive.
File-by-file with a full-featured backup application
Performance impact: VARIABLE.
File-by-file backup with a full-featured backup application can be fast enough if the average file
size is at least 64 k and there are not too many fragmented files. Full-featured backup applications
also offer the best speeds for single file restores and allows for backing up only specific data.
Check the compatibility matrix on the EBS website for a list of full-featured backup applications
supported on your operating system for your library: www.hp.com/go/ebs.
If the average file size is less than 64 k or if the file system is very fragmented, file-by-file backup
will have poor performance. If the file system has a lot of fragmentation, use a de-fragmentation
utility to make the files contiguous again. If the average file size is less than 64 k, HP recommends
that you use a sequential/image backup that backups up the hard drive or LUN image instead of
the individual files. The drawback with sequential/image backups is that they may only be able
to restore the entire disk image and not individual files. If they can restore individual files, the
restore operation will be very slow.
File-by-file with a native application
Performance impact: POOR.
Native backup applications based on tar, cpio, NT Backup, etc. do not have the extra features
needed to manage the bandwidth requirements of the faster tape drives and should only be used
to test basic functionality.
To get the best backup and restore performance, use a full-featured backup application. If the
average file size is less than 64 k, use a sequential/image backup for best performance. However,
a sequential/disk image backup might not allow you to restore individual files or the restore process
will be very slow.
Disk image, flash, or sequential
Performance impact: GOOD.
A disk image or sequential backup backs up an entire disk, partition, or LUN by looking at the
disk sector by sector instead of file by file. The entire disk contents is backed up contiguously,
without the disk seeking, which prevents performance degradation caused by small or fragmented
files.
If you are more concerned about backup performance than single-file restore, disk image or
sequential backups can offer a real performance benefit. The disadvantage is that backup and
Performance problems 157