drobopro and iSCSI / why that slow?

[snafroth]

Hi there,

I finally got my drobopro. Using it via usb/firewire on a mac/win workstation is really nice and fast.

So i decided to use it via iSCSI as storage on my small esx.

The intel dual nic works fine - e.g. large file transfers to guests proof this.

I was able to set up a dedicated vswitch, connected the drobopro, i am able to get the LUNs. fine.

but: once they are active and mapped into /vmfs/volumes everything is really slow. e.g. ls /vmfs/volumes takes 15 seconds. editing a LUN / rescanning hosts 5 minutes.

copying from internal datastore (esata) to a datastore connected via iSCSI: 1,2 gb - 15 minutes.

any hints?

thanks a lot!

seb

added some config screenshots

[snafroth]

upcoming weekend i´ll try to connect the drobopro to a vista machine to test speed.

i´m quite sure this is irq related - but I do not know how to debug this one.

btw: if someone wants to take care of it - he will get paid. thanks!

[Paksk]

So, after further testing, I put the fault on the Software iScsi adaptor that ESX uses. I created a VM with Win2k3 server and drobo connected through iScsi and the speeds were nice and steady. I've ordered a iSCSI PCIE adaptor and will see if hardware iSCSI adaptor will give better results. If not, I will have to use a VM win2k3 server to connect the drobo using iscsi and then create a NFS to map into the ESX.

[J1mbo]

Re auto-negotiation. Whatever you choose it is imperitive that it is the same at both ends. You cannot mix (i.e.) 1000/F and auto/auto.

Re software iSCSI. There was some discussion about this a while ago and it transpired that the software iSCSI initiator depends on ethernet flow control being enabled; the vSwitch is not wirespeed in this respect. I would check this is enabled (and supported) by all components.

HTH

[snafroth]

Hi Paksk,

can you send screenshots of the vmnetwork config as well as the windows iscsi settings? Trying to use vista as well as 2008 server - i can see the target but not activate it "authorisation required" - strange!

Thanks,

seb

[Paksk]

snafroth,

I had this issue for a while... and finally figured out that the reason you are getting that problem is because the iSCSI connection on the DroboPro is being occupied by another initiator. Be sure to remove all iscsi datastore and remove the DroboPro target on your esxi and also reboot your DroboPro. Only one iscsi connection is possible on each target so if you connect it to the vista then your 2008 server won't be able to connect to it using iscsi.

I tried to connect the Drobo to the win2k3 using iscsi and creating a iscsi target from win2k3.. Here is my test:

DroboPro ->iscsi->Win2k3->iscsi-VMware ESXi.

Still very intermitten and slow: The problem I think is the way ESXi VMFS writes to the DroboPro. DroboPro does not take the VMFS writing algorhythm very well.

If I share a local drive from win2k3 as a iscsi to VMware ESX, the speed is perfectly fine.

localdrive (win2k3)-->iscsi-> VMware ESXi

I'm now testing the following:

USB 2.0--->Hardware win2k3 ->iscsi-->VMware ESXi

Will let you know how this goes.

[DSTAVERT]

I don't know if you have a choice within drobopro software but if you do try choosing "file based access" as opposed to block based. While we think of iscsi as block based each vmdk is just a big file.

[corndog]

Just a quick note - I would not be too quick to absolve the DroboPro of "blame" for iSCSI problems. As of now, even trying to connect to a DroboPro from Linux causes the DroboPro to go into a reboot-loop and lose data. This is even though many many other targets work fine with the same Linux initiator.

Just sayin'

[quocx]

For performance reason, use 8MB block size when working with VMFS LUN on DroboPro.

[afertmann]

Hey all,

Not sure if anyone saw this... Looks like Data Robotics published a whitepaper on how to setup the Drobo with ESX3.5.

http://www.drobo.com/pdf/VMware_Best_Practices_1009.pdf

Didn't see a paper for ESX4 though.

-Alex

[BradMDRI]

The DroboElite has been certifide on vSphere 4 and there will soon be a "Best Practices Guide" published on www.Drobo.com. The DroboPro has been certifide on 3.5 and the link to the catalog page is:

http://www.vmware.com/resources/compatibility/search.php?action=search&deviceCategory=san&productId=...

Be sure to use the whole link or simply search for "Data Robotics" in the Compatibility Guide to find listings for both the DroboPro and DroboElite.

[SamWiseTx]

I have a new Dell 2950 running ESX 4.0 U1 and a Drobo Pro using a Dell Power connect 3324 running on it own iSCSI network. Sometimes the drobo gets disconnected and I have to reboot the drobo and rescan the lun to reconnect. Does anybody have a suggestion on a better swtich. I am looking to upgrade the switch since I cannot have this happending during production time.

Thanks

DEL2950 <--

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>DELL_SWTICH<--

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>DroboPro

[Josh222]

I am seeing the same symptoms. Dell R710 running ESX 4.0 U1 & Drobo Pro connected directly w/ crossover. Lately it seems when accessing the iscsi lun through the vm we are losing connection to the drobo. The host often tries to re-establish connection to the drobo automatically, though sometimes gets stuck in a disconnect/connect loop or just hangs altogether and I have to reboot the drobo.

Anyone else have experience with this or tips on how to resolve?

[BradMDRI]

One of the key things is to ensure that the DroboPro firmware is up to date. The current release is 1.1.5 and you can find it at http://www.drobo.com/support/updates.php. You will need to run the Drobo Dashboard software on a PC or Mac to update the DroboPro firmware.

[Josh222]

little update... I found some documentation regarding configuration & best practices setup of DroboPro on ESX3.5, and DroboElite on vSphere, but nothing referencing DroboPro on vSphere. I contacted DataRobotics to ask about support of DroboPro on ESX4, specifically referencing these discconnect issues I (and others) have been seeing and following is their response:

Hello Josh,

Thank you for contacting Data Robotics Technical Support.

At this time DroboPro does not work with vSphere, only the DroboElite.

Not what I was hoping to hear, but oh well... guess I'm on my own.