Scsi reservations esx 5

[johnxgr]

Hello,

we are going to have a project with 48x900gb sas hitachi hus.migration the vms from old storage to hitachi.

There are 100 vms mostly windows 7,some linux.5 esx hosts per fiber channel switch and one storage and with isl connected with other 5 hosts and other storage.

Because the disk are too big i am thnking for a mix of raid 5 7+1 and 2 raid 10 raid groups in 2 pools from hitachi,wide stripping.

but when i present too big lun in esx will be a problem of scsi reservations?or it is only when i have too many intensive vms in one datastore?i want to keep 1 lun=2 datastores.

Hitachi has 2 controllers.all luns i will present from 2 ports in each controller or is better one port per controller ?every esx should see tha same luns.is it correct as implementation?its my first project and i dont have too much experience.

[mcowger]

HUS and ESXi 5 both support VAAI.  As a result, by default, SCSI reservations won't be needed (VAAI takes care of it).

[johnxgr]

So that means that i can make a big datastore from a lun.the thing gets better when i share the vms at this datastore in different hosts?there will be no problem!

and if i make from a lun 2 or 3 datastores is the same.then its only the management reason.

and another question.when i create a pool in hitachi vaai works? And with wide striping in the pool in all raid groups!

[mcowger]

I don't understand any of what you just asked.

[johnxgr]

I meant the following.

because of the big disks and when i ll build raid 5 the lun will be big.generally will be a problem to present to esx 5 tb as a datastore?

or is better to split it in half?make sense that due to scsi reservations?

As a general rule when i split a lun and in each one i have vms the queue is one.for perfomance reasons plays no role to split it?

and vaai in hitachi works when i have a pool of raid groups and withe the selection wide stripping enabled?

[mcowger · Accepted solution]

johnxgr wrote:

I meant the following.

because of the big disks and when i ll build raid 5 the lun will be big.generally will be a problem to present to esx 5 tb as a datastore?

ESXi 5 can support this no problem. 

or is better to split it in half?

Posibility - you should consider that a single LUN only has a single queue, which can present a perofrmance problem.

make sense that due to scsi reservations?

There are no SCSI reservations.

As a general rule when i split a lun and in each one i have vms the queue is one.for perfomance reasons plays no role to split it?

Queues absolutely make a difference.

and vaai in hitachi works when i have a pool of raid groups and withe the selection wide stripping enabled?

You have to ask Hitachi that.