What is best lun/hyper size for VMware using VMAX disks?

Question

Hi,

Would like to find out what is good size for vmax luns presented to VMWare. We are thinking to use 2 TB luns but not sure what is best practice. Also, what is good hyper size for 2 TB meta volume. We are using SMC so I can create bunch of hypers and make a meta volume using SMC. Other applications on this vmax has 16.8 GB hyper volume and 4-way metas but if I use same size hypers for 2 TB, there will be 100+ hypers and I don't think that is a good idea. Can someone share their config with VMware using VMAX disks?

Thanks in advance,

-YP

dynamox · Answer

we are using 250G striped metas built out of 17G symdevs. The more VMs you place on the same VMFS file system the more locking is happening, performance suffers. Look at VMware best practices in terms of how many VMs they recommend per datastore. For VMs that need a lot of space we use RDMs.

Lars4_bf562a · Answer

If you are using vSphere 4.1 the VMFS file system has implemented some new VMFS locking mekanism (i have no personal experiance from this) "allowing" you to have very large devices (e.g 2TB) presented to a vSphare 4.1 server without loosing performance. In previous versions we used 250 GB(- 500) LUN's to keep IO queuing away.

/Lars

dynamox · Answer

Lars, Are you referring to VAAI ? You could create up to 2TB file system before it’s just with VAAI that has yet to be introduced on VMAX vSphere will be more efficient at vmfs locking.

YatinPatel · Answer

Thanks everyone, this helps us a lot, we will be using 2TB luns since we have 4.1. Thanks again, -YP

dynamox · Answer

this would be a good read http://virtualgeek.typepad.com/virtual_geek/2009/03/vmfs-best-practices-and-counter-fud.html

Lars4_bf562a · Answer

Yes you are correct I was thinking of VAAI, and a V-MAX with 5875 or other array supporting Hardware Accelerated locking.... + with the VMFS3.HardwareAcceleratedLocking set to 1.....

So before "we" have THAT I'm skeptical to large LUN's if performance is a issue.

/Lars

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What is best lun/hyper size for VMware using VMAX disks?

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