Hi Guys,

I'm just looking for some non BS answers. I am a complete noob when it comes to SAN's in general. 12 months ago we implemented a virtual environment which included the NX4 implementation. EMC designed and installed the installation and we took all their reccomendations. The basic architecture goes like this.

NX4 with dual datamovers and 10Gbe

12 x 600GB SAS

6 x 1TB SATA

the 12 SAS drives were split into two raid 5 groups of five drives each with two global hotspares, the sata disks were put into 1 raid 5 group. The data movers are connected via 10Gb ethernet to HP6120 blade chassis switches inside an HP BL6000 blade chassis.

All our hosts exist inside the blade chassis and therefore use the same 10GB switch, they include some Vmware ESXi servers and some Windows 2008R2 hosts. The ESXi hosts are accessing the datamovers via NFS and the windows machines are also accessing CIFS data.

Our problem is generally very poor write performance. Our virtual environment for the most part works ok, anything write related appears to be slow but for the most part appears to work. On our physical windows boxes we are seeing some slow numbers for write performance. I must admit no one really complains accessing word docs etc but something doesn't feel right. I can read a 2GB iso from the cifs share to a windows host connected to the same blade switch as the NX4 at approx 190Mbps. If I copy the same file back to the share it copies at about 12MBps. I've tried other hosts in my environment connected to different switches etc and it is never any different, SMB1 or 2 makes no difference. It makes little difference whether I use the sata or sas drives share, it is always the same write performance. My suspicion although hard to measure is the virtual environment has similar performance because if i do the same copy test using the virtual machinesI get roughly the same performance as the physical hosts.

I have contacted the support team and they checked it out remotely and basically said it is all fine. I am basically discounting the network as the problem as the read speed is pretty good, it seems like something inside the NX4 is the bottleneck. I am not using CAVA or deduplication. There are no errors reported on the switch ports.

That write performance is utterly crap in my opinion, my laptop drive can write faster than that, a standard HP windows file server I installed recently could write at over 100MBps. I refuse to believe this NX4 should be that slow.

One question I always had was EMC's decision to use clarsas_archive instead of clarsas_performance in the AVM profile, they said it made no difference, if that was the case why not use the one with the better name to put my concerns at ease, lol.

Yes I know I might be missing something here but I'm just scratching my head wondering why it could be that slow. Could you please share your opinions and if possible the kind of performance numbers you have experienced.

Thank You