Installation and User's Guide

Related concepts“Considerations for Unicode-enabled clients” on page 394Related reference“Autofsrename” on page 310“Detail” on page 338“Query Filespace” on page 593“Restore” on page 613“Retrieve” on page 648Incremental backups on memory-constrained systemsIncremental backup performance suffers if the system has a low amount ofmemory available before starting the backup.If your system is memory constrained, specify the memoryefficientbackup yesoption in your client options file. This option causes Tivoli Storage Manager toprocess only one directory at a time, which reduces memory consumption butincreases backup time. When you specify yes, Tivoli Storage Manager analyzes onlyone directory at a time for backup consideration. If performance remains poor,check your communication buffer settings and the communication link betweenyour system and the Tivoli Storage Manager server. If your system is not memoryconstrained, setting the memoryefficientbackup option to yes degrades your backupperformance.Related reference“Memoryefficientbackup” on page 413Incremental backups on systems with a large number of filesThe client can use very large amounts of memory to perform incremental backupoperations, especially on file systems that contain large numbers of files.The term memory as used here is the addressable memory available to the clientprocess. Addressable memory is a combination of physical RAM and virtualmemory.On average, the client uses approximately 300 bytes of memory per object (file ordirectory). Thus for a file system with one million files and directories, the TivoliStorage Manager client requires, on average, approximately 300 MB of memory.The exact amount of memory used per object varies, depending on the length ofthe object path and name length, or the nesting depth of directories. The numberof bytes of data is not an important factor in determining the Tivoli StorageManager backup client memory requirement.The maximum number of files can be determined by dividing the maximumamount of memory available to a process by the average amount of memoryneeded per object.The total memory requirement can be reduced by any of the following methods:v Use the client option memoryefficientbackup diskcachemethod. This choice reducesthe use of memory to a minimum at the expense of performance and asignificant increase in disk space required for the backup. The file descriptiondata from the server is stored in a disk-resident temporary database, not inmemory. As directories on the workstation are scanned, the database is108 IBM Tivoli Storage Manager for Windows Backup-Archive Clients: Installation and User's Guide