RecommendationsPerformance impactAverage file size
None.
GOOD. Large files let the disk do less
seeking and spend more time doing
continuous reads.
>1 mb: large files
None.
None. File size is irrelevant for Image or
sequential backups.
Image or sequential
backup
File system type
The file system determines the organization of the files on the disks. When the files are spread over
multiple disks with multiple controllers, some disks can be seeking while others are reading. Find the
performance impact of your system's file system in Table 28
Table 28 Performance impact of various file systems
RecommendationsPerformance impactFile system
None.
GOOD. Disk arrays typically provide
excellent access to data. They usually
include many disks, which improves
bandwidth.
Disk array
To achieve optimal performance, your array
must support the following transfer rate:
• LTO-2 HH: 48 MB/s
• LTO-3 HH: 120 MB/s
• LTO-4 HH: 160 MB/s
• LTO-5: 280 MB/s
Also, make sure that the server or workstation
is used as little as possible during the backup,
and close down programs such as virus
scanners, which check each file that is
opened.
VARIABLE. RAID uses a group of disks
to improve performance, and in the
case of RAID 5, provides some parity
protection in case one of the drives
fail.
Server or workstation
with RAID
Upgrade to a disk array or RAID 5 with the
minimum number of disks needed for your
tape drives, or use concurrency or
multithreading in the backup software to pull
from more than one disk at a time. The
drawback with concurrency or multithreading
is that it slows the restore operation.
Also, make sure that the server or workstation
is used as little as possible during the backup,
and close down programs such as virus
scanners, which check each file that is
opened.
POOR. A single disk cannot retrieve
or write data fast enough for any of
the supported tape drives.
Server or workstation
with a single disk
(spindle)
Connection from the host server to the disks
The connection between the host server and the disks determines how much data can be transferred
from the disks to the host computer at a time. A connection with insufficient bandwidth cannot provide
HP StorageWorks 1/8 G2 Tape Autoloader User and service guide 119
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