Storage optimize

Tips for using the EMC VNX2 storage array

Get an overview of EMC's VNX2, including its various models and solution suites. Also, read about some of the differences if you're used to the CX series or VNX1.

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In September 2013, EMC released its next generation of mid-market storage arrays, the VNX2. This release is a complete re-write of the code used in the previous generation. Among other things, this array is designed specifically for use of optimizing performance via tiered storage, especially flash or solid state drive (SSD). (For information on other storage tiers, read Scott Lowe's article on how SAS, Near Line SAS, and SATA disks compare.)

The VNX2 comes in five models. All of the models can be unified, meaning they can have both File and Block capabilities.

  • VNX5400 has up to 250 drives (2.5" and 3.5" Flash, SAS, and NL-SAS) and 1000 GB Fast Cache.
  • VNX5600 has up to 500 drives (2.5" and 3.5" Flash, SAS, and NL-SAS) and 2000 GB Fast Cache.
  • VNX5800 has up to 750 drives (2.5" and 3.5" Flash, SAS, and NL-SAS) and 3000 GB Fast Cache.
  • VNX7600 has up to 1000 drives (2.5" and 3.5" Flash, SAS, and NL-SAS) and 4200 GB Fast Cache.
  • VNX8000 has up to 1500 drives (2.5" and 3.5" Flash, SAS, and NL-SAS) and 4200 GB Fast Cache.

The VNX has always come with solution enablers, or software suites, for which you can buy licenses.  All VNX arrays have the capability to use these features, but the licenses need to be purchased to enable them. The software suites are:

During a recent installation of a VNX2, I noticed there are major differences if you're used to the CX series or VNX1. A big one is the way hot spares are used.

In the older versions, you specified a particular disk as your hot spare. For example, if a disk died in a RAID group or storage pool, you knew that Disk 14 in DAE 1 was the hot spare and would become part of that RAID group temporarily. This is no longer the case. There's now a Hot Spare Policy that you need to set up. The administrator is not in control of which disk is chosen. You can pick how many disks to reserve for each disk type, but you can't say which one. Also, these disks remain unused; they are not configured as hot spares until it comes time to use them. Look at how the Hot Spare Policy is set up in Figure A.

Figure A

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Also, the hot spares are no longer temporary. So if a disk fails and one of your unused disks is used as the hot spare, it will stay in that RAID group or storage pool unless you manually take it out. This could mean a few things. If you're using a larger disk as a hot spare, you may lose some of your capacity. Also, if you have configured redundancy based on your shelves and the buses they're on, this might get tricky; you may lose control of that redundancy as well.

A pretty cool feature is that after you create your storage pools, RAID groups, and/or luns, you can use the disks while they are zeroing. In the older arrays, these disks would be unavailable. I don't know if it might run a little slower, but the performance hit would be temporary.

Something to keep in mind is that the new VNX has different power requirements. While the older arrays could use 110v or 220v and it would auto-detect, the new arrays require 220v.

Summary

The VNX2 is built to be much faster than any of the earlier arrays. It's still early, so many customers are waiting until the bugs get worked out before purchasing a VNX2.

If you've had any experiences with a VNX2, please describe them in the discussion. I'm curious to hear what people think of this release.

 

About

Lauren Malhoit is a VMware vExpert '12, '13 and a member of the EMC Elect. She works as a Solutions Implementation Engineer at Network Storage Inc., where her main concentrations are on VMware, EMC, and Cisco. She has a degree in Computational Mathem...

2 comments
clayman88
clayman88

Good info. I wasn't aware of the changes to the hot spare configuration. I'm not exactly loving the idea of loosing control over which disks are chosen for hot spares.

DavyPaul
DavyPaul

@clayman88 I'm in the process of commissioning my VNX5600 atm. Reading the white papers, there is little to no advantage in retaining the link between enclosures, raid groups etc. I'm going to 'run with' the hot-spares policy and let the machine look after itself. I'll be using mine in a 1:2 split, block:nas with thin provisioned LUNs for block and 'fat' luns for file, but with thin-provisioned filestores. 2 VNX5500 & 3 VNX5300 (plus 5 VNXe 3300) globally and I intend not to make the same mistakes with this new array!