Tsm Deduplication Guidelines - HP StorageWorks 12000 - Virtual Library System EVA Gateway Manual

Command
TCPWINDOWSIZE
BUFPOOLSIZE
TXNGROUPMAX
EXPINTERVAL
SELFTUNEBUFPOOLSIZE
MOVEBATCHSIZE
MOVESIZETHRESH
LOGPOOLSIZE
1
These settings have been tested and verified on all EBS-supported platforms. However, there may be additional factors
that might require further adjustments of these variables. See the IBM Tivoli Storage Manager Performance Tuning Guide,
available on the IBM support web site, for more information.
Table 29 Recommended Settings for each Backup-archive Client's dsm.sys File (dsm.opt File for
Windows)
Command
TCPBUFFSIZE
TCPNODELAY
TCPWINDOWSIZE
LARGECOMMBUFFERS
TXNBYTELIMIT

TSM Deduplication Guidelines

In addition to the TSM general guidelines, the following guidelines apply to a VLS with deduplication
enabled:
• Incremental forever: The TSM (Tivoli Storage Manager) "incremental forever" scheme of backups
are all effectively treated as full backups by the deduplication, so every new backup is compared
against the previous backup. With file server backups that contain just the modified files, this may
result in lower deduplication ratios because most or all of the new backup data is unique, but
database backups (which are normally the entire database every time) will give normal deduplic-
ation ratios.
• Mount retention: You must set the mount retention to 0 (zero) for your server configuration as follows:
dsmadmc -id=admin -pass=admin update devclass <vtlclass> mountret=0
Substitute the password for "admin" above with your TSM server admin password.
200 Virtual Library Systems
1 Value
63
32768
256
0
NO
1000
2048
2048 to 8192
1 Value
32
YES
63
YES
2097152
Notes
Default
Default
Default
Default = 24. When setting this to
0, use an administrative schedule
to execute expiration at an appro-
priate time each day. A value of
0 means the expiration must be
started with the EXPIre Inventory
command.
Default
Default
Default
Default = 512
Notes
Default
Default
Default
Default = NO
For backup to tape/virtual tape
only.