Qsan XCubeSAN XS5224D, Руководство пользователя

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Data Backup
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Figure 12-10 Host data I/O Route
On Linux and UNIX platforms, a command named sync can be used to make the operating
system flush data from write cache to disk. For the Windows platform, Microsoft also
provides a tool –
sync , which does exactly the same thing as the sync command in
Linux/UNIX. It will tell the OS to flush the data on demand. For more information about sync
tool, please refer to http://technet.microsoft.com/en-us/sysinternals/bb897438.aspx
Besides the sync tool, Microsoft developed VSS (volume shadow copy service) to prevent
this issue. VSS is a mechanism for creating consistent “point-in-time” copies of data known
as shadow copies. It is a coordinator between backup software, application (SQL or
Exchange…) and storage systems to make sure snapshots can occur without the problem of
data-irregularities. For more information about the VSS, please refer to
http://technet.microsoft.com/en-us/library/cc785914.aspx . QSAN storage systems fully
support Microsoft VSS.
Run Out of Snapshot Space
Before using snapshot, a snapshot space is needed from pool capacity. After a period of
working snapshot, what if the snapshot size over the snapshot space of user defined? There
are two different situations: