HP StorageWorks 6000 HP StorageWorks VLS and D2D Solutions Guide (AG306-96028, - Page 200

TSM Deduplication Guidelines

Page 200 highlights

Command1 Value Notes TCPWINDOWSIZE BUFPOOLSIZE TXNGROUPMAX 63 32768 256 EXPINTERVAL 0 SELFTUNEBUFPOOLSIZE NO Default Default Default Default = 24. When setting this to 0, use an administrative schedule to execute expiration at an appropriate time each day. A value of 0 means the expiration must be started with the EXPIre Inventory command. Default MOVEBATCHSIZE 1000 Default MOVESIZETHRESH 2048 Default LOGPOOLSIZE 2048 to 8192 Default = 512 1These 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) Command1 Value Notes TCPBUFFSIZE 32 TCPNODELAY YES TCPWINDOWSIZE 63 Default Default Default LARGECOMMBUFFERS TXNBYTELIMIT YES 2097152 Default = NO For backup to tape/virtual tape only. 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 deduplication 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 mountret=0 Substitute the password for "admin" above with your TSM server admin password. 200 Virtual Library Systems

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Notes
Value
Command
1
Default
63
TCPWINDOWSIZE
Default
32768
BUFPOOLSIZE
Default
256
TXNGROUPMAX
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.
0
EXPINTERVAL
Default
NO
SELFTUNEBUFPOOLSIZE
Default
1000
MOVEBATCHSIZE
Default
2048
MOVESIZETHRESH
Default = 512
2048 to 8192
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)
Notes
Value
Command
1
Default
32
TCPBUFFSIZE
Default
YES
TCPNODELAY
Default
63
TCPWINDOWSIZE
Default = NO
YES
LARGECOMMBUFFERS
For backup to tape/virtual tape
only.
2097152
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.
Virtual Library Systems
200