Installation manual

Shadowing a Volume
Configuring a Shadow-Copy Rule (Source Switch)
15-18 CLI Storage-Management Guide
left open for the duration of the shadow-copy run. Some common Microsoft
applications, such as Microsoft Word, hold a file open for writes as long as the client
application is working with the file. (Note that other applications, such as Notepad
and WordPad, open the file only long enough to read it into memory; these
applications rarely pose a problem for the shadow-copy operation.)
You can use the
allow-shared-access command to open each file with all access types
allowed: read, write, and delete. These access permissions make it possible to read a
file even if another application is writing to it or deleting it at the same time. This
introduces the risk of copying files between writes, so that the shadow-copy of the file
is compromised. Use the
allow-shared-access command only if this risk is acceptable:
allow-shared-access
For example, the following command sequence causes “DRrule” to allow unlimited
access to files as they are copied:
bstnA6k(gbl)# namespace wwmed
bstnA6k(gbl-ns[wwmed])# volume /acct
bstnA6k(gbl-ns-vol[wwmed~/acct])# shadow-copy-rule DRrule
bstnA6k(gbl-ns-vol-shdwcp[wwmed~/acct~DRrule])# allow-shared-access
bstnA6k(gbl-ns-vol-shdwcp[wwmed~/acct~DRrule])# ...
This makes it very likely that this shadow-copy rule, “DRrule,” will successfully copy
any open file.
Allowing Only Reads During the Shadow Copy
By default, the shadow-copy rule only allows read access from other applications
while it copies a file. This ensures that no other application can change or delete the
file in the middle of the copy operation, but it also makes it more likely that the rule
will fail to copy some previously-opened files. To return to this default, use the
no
allow-shared-access
command:
no allow-shared-access
For example, the following command sequence causes the “insurDR” rule to block all
writes and deletes while it copies files:
bstnA6k(gbl)# namespace insur
bstnA6k(gbl-ns[insur])# volume /claims
bstnA6k(gbl-ns-vol[insur~/claims])# shadow-copy-rule insurDR
bstnA6k(gbl-ns-vol-shdwcp[insur~/claims~insurDR])# no allow-shared-access