HPE 3PAR StoreServ Storage

What is the Maximum number of Simultaneous disk failures that can be handled by 3PAR

 
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binu_mathew
Frequent Advisor

What is the Maximum number of Simultaneous disk failures that can be handled by 3PAR

Hi

 

I would like to know the Maximum number of Simultaneous  disk failures that can be handled by 7400c with 4 node storage without any data loss.

 

I have the below configuraton

 

56x SAS 1.8TB in RAID 5(7+1)

 

16x 480 GB SSD in RAID 1 ( adaptive cache)

 

1) I believe FOR RAID 1 I can tolerate upto 8 drive failure as its mirrored . Please confirm .

 

2) But what about the sas disks if I configure a single CPG with 56 drives ?

 

 

 

 

 

 

5 REPLIES 5
Sheldon Smith
HPE Pro

Re: What is the Maximum number of Simultaneous disk failures that can be handled by 3PAR

RAID5, one disk.

RAID6, two disks.

 

Period.

 

Anything beyond that involves luck.


Note: While I am an HPE Employee, all of my comments (whether noted or not), are my own and are not any official representation of the company

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binu_mathew
Frequent Advisor

Re: What is the Maximum number of Simultaneous disk failures that can be handled by 3PAR

Hi,

 

Then what does RAID 5(7+1) means.. Is it for every 7 disk one parity disk or for every 7 data one parity block ?

 

 

 

Is there any option in 3par to add more hot spare disk in RAID 5

 

Or Is there any option to increase the disk failure protection level other than RAID 6

 

Kindly suggest the best ..

Sheldon Smith
HPE Pro
Solution

Re: What is the Maximum number of Simultaneous disk failures that can be handled by 3PAR

RAID 5(7+1) means for every 7 data chunklets, there is one parity chunklet.
The 3PAR does not have hot spare disks. There are spare chunklets reserved on each physical disk; if a physical disk (starts to) go bad, the RAID 1/RAID 5/RAID 6 chunklets in use on that physical disk are either moved or regenerated on spare chunklets elsewhere in the array.

 

So with your earlier example, logical disks spread over 16 physical disks using RAID1, 8 disks could fail and if they are the "right" 8, it would still be operational, although degraded performance. If the two disks providing mirrored chunklets both go bad, access stops.

Likewise 56 RAID5(7+1): 7 disks could fail and if they are the "right" 7, it would still be operational, although degraded performance. If two disks in a single RAID5 both go bad, access stops.

 

So what is supported? Like I said before:
RAID5, one disk,
RAID6, two disks.
Period.

Anything beyond that involves luck. If you can predict which disks are going to fail, why are you wasting time in IT? Head to Vegas!


Note: While I am an HPE Employee, all of my comments (whether noted or not), are my own and are not any official representation of the company

Accept or Kudo

dex-mase
Advisor

Re: What is the Maximum number of Simultaneous disk failures that can be handled by 3PAR

hello,

If I have 40 sas disk and 16 ssd disk and 36 NL disk configured using Adaptive optimizzation with CPG R5 before lose data.

How many disk could I lost?  2 for single tier?

 

thanks

 

Luigi

 

Sheldon Smith
HPE Pro

Re: What is the Maximum number of Simultaneous disk failures that can be handled by 3PAR

RAID 5? Disks? One.

If all three CPGs (SSF, FC, NL) are RAID 5, you could lose one of each device type. After the chunklet movement is done for a CPG, then that CPG could lose one more,

How many are you planning to lose before you start replacing with new good drives? <smile>


Note: While I am an HPE Employee, all of my comments (whether noted or not), are my own and are not any official representation of the company

Accept or Kudo