I don't believe it's possible to avoid the 'spare drive' requirements unless you have the minimum configurations only.

From the "Hot Spare configuration on VNXe3200"; kb191137

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On the above there can be exceptions under below circumstances(As discribed on Unisphere Help page):

Minimum Configurations:

1. RAID-5: System with Just 6 drives, configured as RAID-5 (4+1) and 1 Hot Spare Candidate

2. RAID-6: System with Just 8 drives, configured as RAID-6 (6+2) and 0 Hot Spare Candidate

3. RAID-1/0 (Manual mode only): System with Just 6 drives, configured as RAID-1/0 (3+3) and 0 Hot Spare Candidates

For example:

On an array, there are 14 mixed drives(6 SAS+8 NL SAS). It cannot be considered as minimum configuration so we need at least one hot spare disk. Which is as per design

Software Version: 3.0.0.2960754

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Hi Suolim,

Here is Hot spare policy on VNXe. According to the content that VNXe reserves one spare disk for every group of 1-30 disks, there may not be enough disks to support you to complete RAID10 (3+3) and RAID5 (4+1)  configuration.

VNXe uses permanent hot sparing to replace a disk that has failed or faulted. Any unused disk in the system with the appropriate disk technology and size can be used to replace a failed or faulted disk in a storage pool. All VNXe configurations, except for the minimum configuration (a 12 disk NL SAS configuration) require the use of hot spares. When you create or expand pools for all other configurations, VNXe prevents you from configuring all available disks, so as to leave some disks as hot spares.

The VNXe hot spare policy follows these rules to determine how many disks are left as spares:

•In general, VNXe reserves one spare disk for every group of 1-30 disks that have the same type, capacity, and rotational speed (or Flash type). For example, if there are 40 300-GB, 15K-RPM SAS disks in the system, VNXe reserves two of those disks as hot spares.

•VNXe does not reserve a hot spare disk for:

     ◦Systems that have only 8 non-system disks of the same type configured with RAID 6 (6+2)

     ◦Systems that have only 12 non-system disks of the same type configured with RAID 6 (6+2) or RAID 6 (10+2)

     ◦The FAST Cache

     ◦A system disk, unless it has user data on it

•Any unused non-system disk can become a hot spare

•A system disk that does not contain user data can be a hot spare for a failed system disk that has user data.

•A hot spare can be used to replace a failed or faulted disk in the FAST Cache.

•When a hot spare swaps into a pool, it becomes a permanent member of that pool and cannot be used in another pool.

•When a broken disk is fixed, it can be a candidate for a hot spare or used in another pool.

Hi Leo,

thanks a lot for the information

m.

2014-12-15 4:15 GMT+01:00 Leo Li :

ECN VNXe3200

- RAID configuration issue

reply from Leo Li

in *VNXe

Support Forum* - View the full discussion

Hi,

I have a VNXe3200 with 12 x 300GB SAS.

I would like to configure it in a way whereby 11 are in use and 1 hotspare.

Is that possible in a way?

current setup is RAID 5 (4+1) which system calculates only 1.7TB for usage which is alot lesser for default RAID 5

Hi Dennis,

You can create a custom 10+1 RAID 5 Pool and use the remaining drive as a hot spare.

There's some considerations though;

Disks 0-3 are used for the system OE so this reduces the available user space on them by ~ 80GB per drive.

Also remember that it's not a great idea for these disks to be in a pool that is heavily utilized.

HTH.

how do I do that 10+1?....there is no option in the configuration.

Is this a new pool, where the disks are unbound ? The ss indicates you are trying to change/reconfigure.

According to https://emc--c.na5.visual.force.com/apex/KB_HowTo?id=kA0700000004Y8R 10+1 is possible.

• RAID 5 (10+1): (Not for general use) A minimum of 11 disks can be allocated at a time to each pool. Because of the way parity bits are used to provide redundancy, the usable capacity for every 11-disk group is approximately ten disks (91%).

I don't look after a 3200, but on one other 3150 that I do, a 10+1 R5 is configured as a custom pool.

this is what the whitepapers for 3200 indicated.

https://singapore.emc.com/collateral/white-papers/h13058-vnxe3200-intro-wp.pdf

When creating a custom storage pool, users have the option to specify stripe width or choose maximum capacity which will use a best fit algorithm for the available disks. The allowed stripe widths for each RAID type for VNXe3200 systems are as follows:

RAID 5: 4+1, 8+1, 12+1

RAID 6: 6+2, 8+2, 10+2, 14+2

RAID 1/0: 1+1, 2+2, 3+3, 4+4

Thus i was trying to find out other possible means.

I see what you mean, however the KB article I referenced is a later version than in the whitepaper. Maybe one of them is incorrect or is pre-empting a software release.

Maybe log an SR to get clarification.