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Can there be 4 tiers in a FAST/VP policy?
- Can a policy have more than three pools associated with it? Particularly, could you have a RAID-5 EFD tier, a RAID-10 FC tier, a RAID-5 FC tier, and a RAID-6 SATA tier?
- Is it possible to set a pool to read-only. For example, if the answer to the previous question is yes, could you set the RAID-5 FC tier to read-only while you prepare to migrate data to the RAID-10 FC tier?
AranH1
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September 12th, 2013 16:00
It is technically possible but only supported/recommended if the 4th tier is external (FTS).
While Enginuity does not specifically block you from having two FC tiers in a policy they will be treated as equal (they are both FC tiers) and your data placement/movement will be random between those tiers most likely and will not achieve your desired results.
An individual Tier can be comprised of multiple pools of the same disk and RAID type.
Vipin VK
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September 12th, 2013 11:00
Kindly move this discussion to Symmetrix Support Forum by selecting Actions > Move from the right of the page
Anonymous
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5 Practitioner
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274.2K Posts
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September 12th, 2013 16:00
1)There can be only 3 Tiers in the FAST VP Policy and thereby only three pools.
2) No it is not possible to set a pool read-only .
sauravrohilla
859 Posts
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September 12th, 2013 19:00
As AranH said, 4th tier is possible as FTS tier and regarding your second question setting a pool to read only. You can think of rebinding option which is more or less equivalent to setting a pool read only. Rebinding to a newer pool will allow new writes to go to a newer pool and reads to happen from old pool.
regards,
Saurabh
sauravrohilla
859 Posts
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September 12th, 2013 20:00
i just re read your question, rebinding wont help in your case.
regards,
Saurabh
AranH1
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September 13th, 2013 06:00
What I have seen done when the goal is to migrate from one FC tier to another is the following:
1. Add new FC Tier to FAST Policy
2. Rebind all FC bound tdevs to the new FC Tier
3. Remove old FC Tier from Policy
4. Use VLUN Migration to migrate extents from old FC tier only to new FC tier