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How to view existing RAID levels?
I just can't seem to find this in the GUI. Where, whether in CLI or GUI can I see how the storage pool is "constructed" via different RAID groups. Thank you.
brettesinclair
715 Posts
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April 7th, 2015 15:00
From the GUI, if you go to System>Storage Pools. Highlight the Pool and click Details, you get a basic breakdown;
From uemcli, you can use the the pool command. Synax is;
uemcli -d arrayname -u Local/username -p password /stor/config/pool -id poolid show -detail
Just change arrayname, username, password and pool id. If you don't know the pool id, get it by ommitting the id options, which will display the detail for all pools.
PeteWalkerCoreB
3 Posts
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April 8th, 2015 07:00
Thanks Holton. So, the *only* way is to take the time and trouble to learn the capabilities of the EMC SAN in question, and then look at the pool to be able to reverse engineer it? There's no direct way in the GUI or CLI that I could output the RAID groups that make up the storage pool? That seems like an odd way to have to gather this information, instead of it being easily viewable.
HJEWKES
19 Posts
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April 8th, 2015 07:00
Pete,
This information does show what you are asking for. Let me help break it down a little, We see in the screenshot Brett added that the RAID level is RAID 1+0, we also see there are 12 disk's in the pool. On the VNXe 3+3 is a RAID 1+0 so we can conclude that there are 2 packs of 6 disks in this RAID 1+0 pool.
On a side note you can see the same information in Unisphere under > System > Storage Pools > Then highlight the pool you want and go into details. You will see the RAID level and see how many disk's are in the pool. Once you do this here is the breakdown of the RAID levels,
RAID groups supported for VNXe 3100/3150:
Capacity
NL-SAS Disks RAID6(4+2) needs 6 Disks or multiple of 6's
Balanced Performance/Capacity:
SAS Disks RAID5(4+1) needs 5 Disks or multiple of 5s
High Performance:
SAS Disks RAID 10(3+3) needs 6 Disks or multiple of 6s
Best performace:
EFD Disks RAID 5(4+1) needs 5 Disks or multiple of 5s
VNXe 3300:
Capacity
NL-SAS Disks RAID6(4+2) needs 6 Disks or multiple of 6's
Balanced Performance/Capacity:
SAS Disks RAID5(6+1) needs 7 Disks or multiple of 7s
High Performance:
SAS Disks RAID 10(3+3) needs 6 Disks or multiple of 6s
Best performance:
EFD Disks RAID 5(4+1) needs 5 Disks or multiple of 5s
After MR4 two more RAID configuration are supported for VNXe 3100/3150/3300:
RAID 5 (10+1) for SAS and NL-SAS disks
RAID 6 (10+2) for NL-SAS disks
Below is VNXe 3200 RAID configurations
RAIDlevel
Description
Best suited for transaction processing and often used for general purpose storage, as well as for relational database and enterprise resource systems. This RAID level provides a fairly low cost per MB while still retaining redundancy.
RAID Level 5 stripes data at a block level across several disks and distributes parity among the disks. No single disk is devoted to parity. Because parity data is distributed on each disk, read performance can be lower than with other RAID types.
Distributed parity requires all disks but one to be present to operate. If a disk fails it will reduce storage performance and should be replaced immediately. Data loss will not occur as a result of a single disk failure.
- RAID 5 (4+1): A minimum of five 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 five-disk group is approximately four disks (80%).
- RAID 5 (6+1): A minimum of seven 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 seven-disk group is approximately six disks (86%).
- 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%).
Note: If two disks in a RAID 5 disk group fail, this will cause data loss and render any storage in the RAID group unavailable until the failed disks are replaced or the data is restored.- RAID 6 (4+2): A minimum of six 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 six-disk group is approximately four disks (66%).
- RAID 6 (10+2): (Not for general use) A minimum of 12 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 12-disk group is approximately ten disks (83%).
Note: If three disks in a RAID 6 disk group fail, this will cause data loss and render any storage in the RAID group unavailable until the failed disks are replaced or the data is restored.Thank you and please let me know if this helps in determining.
Best Regards,
Holton Jewkes
EMC TSE
PeteWalkerCoreB
3 Posts
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April 8th, 2015 07:00
Hi Brett. Thanks for your input. This is good, but doesn't show me how many RAID sets went into the pool - 4+1, 6+2, etc. and how many of those RAID sets comprise the entire pool. We have a client who wants to uncover this information, as he thinks his currently RAID level is shortchanging him storage space. How can I get that information? Thanks again.
HJEWKES
19 Posts
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April 8th, 2015 08:00
Pete,
Yes this is how it is done. You can also call in and make a request for enhancement on this feature if you would like.
You're welcome
Best Regards,
Holton Jewkes
EMC TSE