storage concern

[Rawat Sunil]

Please clarify my doubts regarding the mentioned storages.

1. EVA 4400

As per our knowledge there is one Mid Plane in the storage that manage both the controllers in case of mid plane failure complete storage will be down. Please clarify the same. If it will happen then what is the rate of chances.

First we have created two aggregate and after that we have created the Virtual disk with the Raid5 and Raid 1 configuration. What will happen if two or more disk will be fail in the storage in two different scenarios first in case of disks failure at same time and in second scenario the disks will fail after some interval of gaps. As per my knowledge in the above scenario the complete storage will be down. If yes what is the frequency of its happening.

2. MSA 2312fc storage

As per our knowledge there is one Mid Plane in the storage that manage both the controllers in case of mid plane failure complete storage will be down. Please clarify the same. If it will happen then what is the rate of chances.

First we have created two aggregate and after that we have created the Virtual disk with the Raid5 and Raid 1 configuration. What will happen if two or more disk will be fail in the storage in two different scenarios first in case of disks failure at same time and in second scenario the disks will fail after some interval of gaps. As per my knowledge in the above scenario the complete storage will be down. If yes what is the frequency of its happening.

3. EVA 4100

First we have created two aggregate and after that we have created the Virtual disk with the Raid5 and Raid 1 configuration. What will happen if two or more disk will be fail in the storage in two different scenarios first in case of disks failure at same time and in second scenario the disks will fail after some interval of gaps. As per my knowledge in the above scenario the complete storage will be down. If yes what is the frequency of its happening.

[gregersenj]

That a "funny" question.

Here's my answer / opinion, according to my best knowledge.

Lest take the Hard drive failure first.
On the MSA.
The MSA is old way of doing things.
If you got a RAID 1 and both drives fail. Simultainiously, or the second drive fail before replacement and rebiuld of the primary drive.
Then you must recreate the RAID, and restore your data from backup.

RAID 5. If you loose 2 drives, same way.
Then you must recreate the RAID, and restore your data from backup.

RAID 10 (1+0 (0+1 Compaq Smart Array)) Is striping a number of RAID 1's.
RAID 10 will survieve mulitble disk failures, unless you loose both drives in one of the mirror sets.

Then you must recreate the RAID, and restore your data from backup.

RAID 50 is stipped RAID 5 sets.
You can loose multible disks, if you loose 1 disk only in each RAID 5 set.
If you loose 2 disks in the same RAID 5 set, you know the answer by now.

The EVA's.
VRAID 1 is RAID 10
VRAID 5 is RAID 50 - Using SubRAIDs of 4D+1P
It's the same failure senario as RAId 10 and RAID 50. Only the EVA's got virtual HOT spare

If you reda the userguide for the smart array 641, you will find a graph, showing the risk of catastrophic disk failure.

The midplanes / backplanes. Do not manage anything !
It is connections only. A printet circuit board has replaced cables.
There's a few "non active" components. There's a NVRAM holding a copy of minor informations like chassis serial number, currently used fw version.

The EVA4400 got a shared management module.
The EVA4400 don't got OCP on the controllers. It's got WOCP on the management module.
Also Command View is on the MM.
You can still use server based CV, wich is faster, and more options.
A dead MM will not take the EVA down.

Having said that. There's a very litle risk, that a failure could take it down.

100% uptime does not excist!! at all.

BR
/jag