What kind of performance should I expect Dell Equal Logic PS5000

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Mackintire

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My company has a Dell Equal Logic PS5000 with dual gigabit connections.

Only one of the nic s are connected at the moment.

It is connected via ISCSI to a VMware 4.0 file server Server 2008 R2 .

The PS5000 is running firmware version 5.0.2


I'm seeing 70MB writes and 30MB reads.

Is this thing supposed to have this crappy level of performance?

We own it but its a purchased server from our hosting provider. They manage the entire thing. The Engineer there is asking me what would I expect to see.

I said I expect to see line speed, close to 100MBps

Frankly, I would accept 70MBps read and write, as at least then I could have them connect up the second nic and configure the VM to use MPIO and THEN I might actually see 140MBps.

Dell says the PS4000 should see 100-110MBps on one gigabit connection.

I have zero SAN experience so I would like some thoughts from all of you.
 
Do you have access to the ESX server networking config?

Is there a dedicated network for storage, or is it being shared with data traffic?
 
Mackintire said:
I'm seeing 70MB writes and 30MB reads.

Is this thing supposed to have this crappy level of performance?
Click to expand...
Yes.

I had a support ticket in with both VMware and Dell about the very same issue a couple of years ago (vSphere 4.1) and after weeks (literally!) of them giving me the run-around, saying that I need a dedicated vlan for vMotion and other shit like that which has nothing to do with the performance of the array they concluded that it is working as intended.

They suggested that I upgrade to SAS drives (mine is loaded with SATA drives) and/or stick some SSDs in there if I want better performance. My array runs in RAID50.

The long and short of it is that the PS series is total crap that can't sustain decent transfer rates at even really low IOPS. It also tops out at about 3,500 IOPS.
 
It is important to first fully understand how important the SAN network fabric is to good performance. The first place to “start” is to look at your setup to see if you have enough “SAN network” to support your data traffic. I would review this document as your starting point: http://en.community.dell.com/techcenter/storage/w/wiki/equallogic-configuration-guide.aspx

It is recommended that you separate your iSCSI traffic from your LAN traffic and this is essential to achieving top performance in a iSCSI environment. The server should have a separate physical connections with at least one NIC facing the LAN subnet, and at least one NIC (or HBA) facing the iSCSI SAN subnet. Also, if you can, multi-pathing is highly recommended for iSCSI performance (i.e., more than one NIC/HBA interface facing the iSCSI SAN).

The second item that typically affects performance is the switch; this should be setup with a separate VLAN for the iSCSI subnet (and not the default VLAN1). The reason for this is that switch manufactures typically follow Cisco and reserve the default VLAN (VLAN1) as the administrative VLAN.

Ensure Flow-Control and Jumbo Frames are setup on the switch and Host interfaces that are facing the iSCSI SAN subnet). The typical rule here is for Switches: set flow-control to “Receive = ON”, for the Host server interface set flow-control to: “Send = ON, Receive = OFF” (or TX enabled, you can also set the host to TX/RX enabled, as this will work also). The array already has both enable, so there isn't any configuration you need to do on the array.

The default VLAN1 should not have Jumbo Frames enabled either. The largest supported frame size on VLAN1 is typically 1600 bytes commonly referred to as a “Baby Giant” in Cisco documentation. It is recommended that user traffic be configured on VLANs other than VLAN 1, primarily to prevent unnecessary user broadcast and multicast traffic from being processed by the Network Management Processor (NMP) of the supervisor.

If your switch doesn’t support both (jumbo and flow), then choose to enable Flow-control. Also, the processor and switch ASIC should be considered when building your iSCSI VLAN. Placing all the iSCSI VLAN ports on one ASIC could result in poor performance. Also an undersized (underpowered CPU) switch can cause performance issues as well so ensure you review the approved HW: http://en.community.dell.com/techcenter/storage/w/wiki/equallogic-validated-components.aspx. Also, each switch has specific settings so you can review recommendations both from the manufacture and the equallogic.com site.

To see if the Array is the bottleneck, you can download the “SAN HQ” which a monitoring tool specifically designed for the EqualLogic arrays. This will help you decide if you have the right RAID policy setup, disk types (SAS or SATA), etc. This can be downloaded for the support site: support.equallogic.com (a valid support login is required).

-joe
 
Thank you for the excellent responses.

Our provider upgraded the VM nic drivers and now the system is bursting to 120MB/s which is significantly better than what we saw before.

We are planning on moving the VM file server front end to physical hardware later in the year.

Thank you again,

Mackintire
 
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