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EVA6400 with 3 enclosures, further expansion with VRAID6

 
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storagetechsol
Occasional Advisor

EVA6400 with 3 enclosures, further expansion with VRAID6

Hi Experts,

 

We have a new setup of EVA6400 at customer site so would like to check if we have any implementation guide / Best practies for a new setup?

 

couple of other questions we have:

 

  1. EVA6400 with 3 enclosures, expanding one enclosure. My question is , when I add the new one , do I need to shutdown the storage system? and how does storage presentation take place with expanded enclosure?
  2. Also some insight on performance of VRAID6 versus VRAID5.. not sure whether it is supported for this implementation.

thx.

 

 

 

P.S. This thread has been moved from Disk-Based Systems > Disk Array >to Storage Area Networks (SAN) (Enterprise). -HP Forum Moderator

 

 

4 REPLIES 4
Jason_L
Valued Contributor
Solution

Re: EVA6400 with 3 enclosures, further expansion with VRAID6

Hello,

 

I believe you are asking about adding disks enclosures online.  Currently you have 3 enclosures and would like to expand to 4. 

 

According to the doc found at:  http://bizsupport2.austin.hp.com/bc/docs/support/SupportManual/c02248317/c02248317.pdf

 

Cabling the enclosure

You can connect a disk enclosure to the EVA while the EVA is online or offline. The offline method is

preferred if downtime is available.

 

The doc explains in further deatails.

 

Some practical advice from going through several of these.  Pay very close attention to the cabling as documented in the above link.  Most of the issues I have seen with installing additional enclosures have been due to cabling the enclosure to the controllers. And if you can get the downtime to do this, that would be preferred as well. If no downtime is available, read through the documentation very carefully.

 

Once you have installed the enclosre and added the disks, then you can add the disks to an existing disk group or create another disk group.  Please keep in mind the number of disks in a disk group affects performance.  The more disks in a disk group, the more spindles on which to stripe data = better performance.  Usually 3 things affect performance based on the config.  Number of spindles, raid type and write penalties, and spindle speed.  Of course this assumes you have the controllers load balanced etc - but I am digressing. So once you add the disks to the disk group, you can then create additional virtual disks and present the virtual disks to a conencted and properly zoned host.

 

As for raid type and performance, really it depends on the I/O characteristics of your workload. If I recall correctly raid 6 uses "double" parity or two seperate parity streams.  So raid 5 will likely perform better in write intensive situations.  There is lots of information available on the performance characteristics of the different Raid types online in various places on the web.

 

From my experience, most people with EVA storage seem to use the R1 or R5 in their configurations.

 

Hope this helps...

 

-Jason

 

 

 

I work for HPE.
Cali
Honored Contributor

Re: EVA6400 with 3 enclosures, further expansion with VRAID6

I have done many Times a Shelf adding to an P6000 and done it always Online.

(Not in Bussiness Hours)

 

Here is an Guide (Page 14):

HP StorageWorks EVA6400/8400 M6412A disk enclosure installation instructions

http://h20000.www2.hp.com/bizsupport/TechSupport/CoreRedirect.jsp?redirectReason=DocIndexPDF&prodSeriesId=3900918&targetPage=http%3A%2F%2Fbizsupport1.austin.hp.com%2Fbc%2Fdocs%2Fsupport%2FSupportManual%2Fc02248317%2Fc02248317.pdf

 

After this only Add the new Disks to your existing Disk Group.

 

Yes, you can configure Raid6, but it will be slower as an Raid5.


======================
I'm not an HPE employee, so I can be wrong.
storagetechsol
Occasional Advisor

Re: EVA6400 with 3 enclosures, further expansion with VRAID6

Thanks guys. I really appreciate your response.

 

Out of curiousity ... you mentioned (Not in Bussiness Hours) so you are suggesting to expand it during out of business hours?

 

what is the impact on I/O performance when I do it online?

Jason_L
Valued Contributor

Re: EVA6400 with 3 enclosures, further expansion with VRAID6

I suggest if you do the addition online its during a scheduled maintenance window, which is usually after business hours.  This is just precautionary in case "something goes wrong".  Like I said please pay close attention to the cabling diagrams.

 

There really would not be much if any performance impact from adding an enclosure.  When you group the disks you may level, which is a background task in which I/O takes precedence, but again performance impact would be very small if any.

 

Like the other poster responded, best case would be to add these disks to an existing disk group for performance reasons, and RAID 5 is typically better performance than Raid 6.

I work for HPE.