HP StorageWorks VLS6109 Virtual Library System AG167A 产品宣传页

Faster backups 

1. (Physical tape) 

7 min 23sec (443 sec) 

29.34 

2. (Virtual tape no compression) 

3 min 10 sec (190 sec) 

68.42 

3. (Virtual tape with compression) 

4 min 12 sec (252 sec) 

51.58 

 
With configuration 1, the backup job must wait for physical tape drives to become available for 
different servers (physical limit of two drives), whereas with the virtual tape backups, a dedicated 
virtual tape drive is allocated to each server, so the backup effectively happens in parallel. 

Data compression within the VLS6000 series is performed in software in the VLS node, and this 
increases the capacity of the VLS6105 in this example from 2.5 TB up to 5.0 TB (with 2:1 
compressible data). The downside is that because the data compression is performed in software, the 
throughput is reduced, as can be seen in the results. 

Faster single file restores 

The next test was to evaluate the restore times from physical media (already loaded in the library) and 
from virtual tape. The physical media recovery time obviously would be longer if it had to be retrieved 
from offsite. The restore consisted of the same single file from approximately 50 percent into the 
directory structure of the backup. 

Time is measured as reported by the backup application start to finish. 

Server 1 from physical tape 

2 min 6 sec ( 126 sec) 

Server 3 from physical tape 

3 min (180 sec) 

Server 1 from virtual tape (no compression) 

22 sec 

Server 3 from virtual tape (no compression) 

20 sec 

 

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