Continuing the X4 Series (not an X4
though since for Quotas we’re only concerning ourselves with a traditional production
and DR setup).
Introduction
It is not directly possible to synchronize Quota Rules
from source to destination, because you cannot create a Quota Policy Rule on a
Read-Only volume. If you are thinking you can break the mirror, set the Quota
Policy Rule, and then resync - like we did in the previous post for applying an
export policy to a destination Qtree - that does not work, the Quota Policy
Rule disappears from the policy.
There are various devices - like WFA, scripts that backup
Quotas to an external database which can then be used to restore the Quota
Policy Rules in a DR situation, Autosupport … - no way though to have the Quota
Policy information actually on-box on the DR SVM, unless …
How to Use CIFS
Comments to Store Quota Information
The answer is to use CIFS share comments (Qtree comments
do not exist at least not in CDOT 8.2.1/2). Essentially, for each volume with
Quota enabled, and qtree with Quota policy rule, we create a specially named
hidden CIFS share, and in the comments we can store details of the Quota. We’re
already synchronizing CIFS shares (see Synchronize-CifsX4.ps1),
so all we need is a tool that creates these special CIFS shares with comments
for Production, and another that can extract the information and apply in DR.
And the tools are the PowerShell scripts posted in Parts
2 and 3. The below diagrams detail the workflow these scripts use.
Note: If you’re
thinking all this seems like a lot of effort, 8.2.X doesn’t have a Vserver/SVM
DR like 7-Modes vFiler DR.
Rules of Quota
Policy Rules
For simplification/standardization, our Quota Policy
Rules follow this format:
1: We only have “tree” type
2: Volumes do not have applied quotas rules - only Qtrees
3: Qtree quotas are either disk-limit or soft-disk-limit
(tracking), and every Qtree has a Quota
4: Tracking Quotas are always a soft-disk-limit 4x the
volume size (so will never alert)
5: If Quota on the Volume is turned off we assume there
are no rules to care about.
Workflow
Schematics
In script planning stages I drew the following
workflows. These workflows are not exactly how the scripts turned out, but they’re
a useful guide to what we’re trying to achieve (I’ll hopefully update them when
I get around to it).
Quota Acquire
Workflow
Figure: Quota
Acquire Workflow
Quota Recover
Workflow
Figure: Quota
Recover Workflow
Comments
Post a Comment