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Query on eva - 6400 hard disks

chindi
Respected Contributor

Query on eva - 6400 hard disks

Hi ,

I have a query , can i dedicate one single hard disk 300gb 15k rpm out of a pool of 68 gb hard disks....from eva -6400...

to a database...??


9 REPLIES
cjb_1
Trusted Contributor

Re: Query on eva - 6400 hard disks

No. And why would you want to?
chindi
Respected Contributor

Re: Query on eva - 6400 hard disks

Hi Cib ,

One of our application vendor's dba said he wanted the same..
bcoz he says he wants dedicated spindles for his database , in order to imprve performance ..i too was confused when he askd for the same..
Actually right nw his databse has 4 mounpoints..all are on internal hard disks..
and we were planning to migrate it to SAN ...

mayb he hasnt workd on san storage ..den...
cjb_1
Trusted Contributor

Re: Query on eva - 6400 hard disks

I think you are right!

Might be wrong but I don't think there's anything to stop you having a single physical disk in an eva disk group that you could dedicate to that server but it would have no resilience and rubbish performance. Add a single lun (which will be striped across all 68 spindles effectively) for the database and should be fine.
Uwe Zessin
Honored Contributor

Re: Query on eva - 6400 hard disks

> I don't think there's anything to stop you having a single physical disk in an eva disk group

That is simply not possible with the EVA.

Virtual Disks live inside Disk Groups and Disk Groups require a minimum of 8 physical Disk Drives (except for SSD Drives where the lower limit is 6).

When I took a training with V1.0 of the EVA, it was possible to initialize a Disk Group with 4 Disk Drives (error in CV-EVA). We tried it with the two training units and one fell in a boot/crash/boot cycle.
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McCready
Valued Contributor

Re: Query on eva - 6400 hard disks

A reasonable request from a DBA would be to have his tables and logs on different spindles. That you can do via creating a second disk group and using it for the virtural disks that are part of the database.
check out evamgt.wetpaint.com and evamgt google group
Viktor Sokol
Occasional Visitor

Re: Query on eva - 6400 hard disks

>> he wants dedicated spindles for his database , in order to imprve performance ..

Whats the point? 300gb virtual volume in a group of 68 drives will be mush faster comparing to performance of one single drive.
How happy dba will be if this single drive will fail? :)
Patrick Terlisten
Honored Contributor

Re: Query on eva - 6400 hard disks

Hello,

you should told you DBA taht 68 drives are much more faster then a single drive. Even in a non-EVA array dedicating a single disk to an server is useless.

Regards,
Patrick
Best regards,
Patrick
klb
Valued Contributor

Re: Query on eva - 6400 hard disks


HAHA, Just give him a 300GB LUN spread as usual across all spindles and tell him it is a single disk.

I'll be he comes back later on and is really impressed with the speed of that disk and will definitely want to know the model of it so he can put it in his tool box for future reference. Tell him it's a "SSRAMD-68-300-50krpm" made by Microsoft. Agree with him that it is just unbelievably fast and that you've been pushing the company to install more of them.

Ask if he will help by sending an email with his testimony added as to the merits of this piece of hardware to the higher-ups so that they may be convinced this is the way to go.

HAHA
Uwe Zessin
Honored Contributor

Re: Query on eva - 6400 hard disks

I hate to disappoint you...
(well, I do not ;-)

but many disks do not automatically mean high performance !!

Think about a single-threaded application that does pure synchronous I/Os.


I had a nice discussion with one customer who had a process run through his database and was disappointed that 'performance (IOPS) was so slow'. Well, I've asked him to fire another process against the database and I could demonstrate (with EVAperf) that the EVA _was_ able to do more work, but the limitation was his application. He then started a 3rd and a 4th process and the EVA still delivered more I/Os.
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