HP StorageWorks 6105 Virtual Library System AF728A 产品宣传页

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AF728A
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In Figure 5, data resident on remote LAN-attached servers and shared storage devices for SAN-
attached servers can be directed to the VLS6000 for backup. The VLS6000 can be configured to 
have as many tape drives (up to 64) and libraries (up to 16) as best meet the backup strategy. For 
example, each of the servers with SAN-attached storage could have their own dedicated tape drive 
(based on capacities being backed up), while groups of remote LAN-attached servers could be 
allocated a tape drive and the backups interleaved onto that single (virtual) tape drive. With more 
virtual tape drives available, the backups will complete faster than the equivalent backup to the 
limited number of tape drives in a physical library.  
The reference to “slow SAN servers” reflects the ability of the SAN server to “push” data over the 
SAN fast enough to stream a physical tape drive. It is therefore dependent on the performance of the 
disk array (from which the data is sourced), the processing power of the SAN server, and most 
importantly the type of data being backed up. For example, Microsoft Windows file/print servers and 
web servers (with many small files) are notoriously slow to back up.  
It should be noted in this example that the LAN-based servers can be backed up to their own virtual 
tape drives, hence improving restore performance because of reduced interleaving. However, the 
overall LAN backup performance will still be limited by LAN bandwidth (about 100 MB/sec for 
Gigabit Ethernet). The example merely illustrates that virtual tape is a seamless integration into an 
existing backup methodology.  
The SAN backups, however, will benefit from increased performance because they now happen 
in parallel. If you have 10 slow SAN servers, you would create 10 virtual tape drives in the 
HP VLS6000 and back up the slow SAN servers in parallel. The performance improvement will also 
depend on the performance level of the SAN-attached disk array. Previously the only option was to 
buy more physical tape drives and expand the physical tape library and then back up the systems in 
parallel, but this option would be expensive. 
The overall backup performance is only limited by the number of Fibre Channel ports, disk array 
performance, and the number of backup streams, but a 10-TB VLS6510 is capable of backing up at 
approximately 400 MB/sec with eight backup streams feeding it. Of course, actual performance may 
vary according to the variables in your particular configuration. 
Because no data is totally safe until it is on physically removable media that can be taken offsite and 
vaulted, the HP VLS6000 backups can be migrated to physical tape using the backup application. 
Remember: the backup application sees both the VLS6000 and the physical tape library as “real” 
libraries and the data stored on the VLS6000 is in tape media format. Therefore, to migrate to 
physical media in a physical tape library means a media or object copy function must be invoked by 
the user from the backup application software.  
In HP OpenView Storage Data Protector, for example, object copy allows multiple backup jobs to be 
merged onto a single physical piece of media, either directly after the backup to VLS, at a future 
scheduled time, or in interactive mode when the user decides it is necessary. 
Storage Data Protector also allows “media copy” where a complete virtual media tape can be copied 
to a complete physical media tape. 
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