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Data Protector Express User's Guide and Technical Reference
3. Some file or application servers may have large catalog files on them, perhaps 1.0 GB or larger.
These files should be assigned to their own streams. To do so, change the
Backup stream
field on the
file’s
Storage page
to
Create new stream
.
In general, when creating or modifying data streams, first use the capacity of the
physical
device to
determine the optimum number of data streams and then create separate streams for very large files. Too
few or too many data streams will impede maximum performance.
You may experience problems with data streams if you have not dedicated any streams to specific
volumes or files. Problems may also occur if you exceed your hardware or operating system capacity.
Other factors that affect job speed
Additional factors that affect job speed include:
File compression:
Whether or not files are compressed by the backup unit affects how fast jobs run. When
a backup device compresses files, e.g., at a ratio of 2:1, a proportionately greater amount of data needs to
be sent to the backup device for it to stream. However, when files are sent across the network already
compressed, as NetWare does, further compression by the backup device will be negligible.
NOTE:
Compression ratios vary among devices.
File encryption:
Depending on your hardware and the level or encryption selected affects how fast jobs
run. When a machine has to use extra resources to encrypt files, a proportionately greater amount of load
is placed on the machine.
Minimize small file size:
Large files transfer and are written to the backup device more efficiently than are
small files. If you can limit the number of small files you back up, especially those smaller than 64K, your
job will run more quickly.
CPU speed:
In general, a faster CPU results in faster backups. Take the speed of the CPU into account
when deciding where to place the backup device and to locate the catalog.
RAM:
In general, additional memory results in faster backups. By default, Data Protector Express allocates
25% of physical memory, up to 32MB per device, for buffering. If you have four devices on one machine,
you should install 512MB of memory (32MB x 4 devices x 4) in that machine. If you have eight devices
on one machine, install 1GB of memory (32MB x 8 devices x 4) in that machine.
NOTE:
Use this as a guideline when attaching devices to each machine.
Working with Permissions
This section provides useful tips for assigning permissions.
Checking the effective permissions of a user
Log on as the user.
On complex installations with multiple users and groups and varying levels of security, a particular user’s
effective permissions can be difficult to identify. The easiest way to identify a user’s effective
permissions is to log on as that user.
If you have not yet assigned the user a password, simply log on as the user. Browse the various
General
page
s of the objects in the catalog. Verify that the displayed effective permissions match your intended
security measures.
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