HP StorageWorks 6000 - Virtual Library System, User Manual

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11. Type the desired policy settings in the corresponding fields. The policy settings differ for SAN
libraries and LAN/WAN libraries, and are as follows:
Figure 47 Setting the echo copy pool policies (LAN/WAN shown)
.
SAN libraries:
• Retention days – the number of days information is kept in the firesafe before it is deleted.
The default is two days.
• Sizing factor – the percentage of space, compared to the actual size of a disk, allocated on
the virtual tape for the copy job. For example, if the sizing factor is set to 90% and the
physical tape is 100 GB, the allocated space for the virtual tape will be 90 GB.
NOTE:
The sizing factor is crucial to creating the right size virtual tapes. When determining the sizing
factor of the virtual tapes, keep in mind the following:
• The sizing factor should be based on the size of the physical tape or the tape type if
possible. Common tape types and their sizes are: LTO-1 – 100 GB, LTO-2 — 200 GB,
LTO-3 — 400 GB, LTO-4 — 800 GB, DLT-IV — 80 GB, DLT-VS1 — 160 GB, SDLT-I —
320 GB, SDLT-II — 600 GB.
• HP recommends against setting the sizing factor too high (for example 110%). Although
the virtual copy can be made, if the drive compression is too low the data might not fit
back onto the physical tape.
• The sizing factor applies to all operations except Load for Restore, in which case the sizing
factor is ignored and the virtual copy is exactly the size of the physical cartridge.
• In general, the virtual cartridge is approximately 90% of the actual cartridge size. Base
the size of the copy on the eventual maximum size of the actual cartridge that is to be
copied.
• Echo Copy on MailSlot Eject – When the backup application ejects an out of sync virtual
cartridge, the matching destination cartridge will not be ejected until the copy is complete.
When the copy on eject option is not checked, then the time to complete the copy and eject
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