horrible slow connection to ESX

[deiruch]

Have you tried attaching the disks directly, not through the PERC 5/iR? I once set up some Dell servers that had disastrous performance. As soon as I used dirt-cheap SATA disks, connected to the board (the mainboard had connectors too), the problem disappeared. I saw the same problems you describe here (except that I wasn't running StarWind on those servers).

[ghost]

In the mean time i switched NICs (now onboard iSCSI <-> PCI-X or PCIe i forgot, normal LAN), still the same.

At the moment i cannot bypass the PERC controller, because Windows is installed on the same disks (Windows no software RAID1 for OS). Another 2 disks i also cannot install because there is no place with "big" DAT drive:
http://www.disasterzone.net/blog/upload ... inside.png
I already discovered that the controller is a lot faster when write cache is enabled, which is no default. With that i had even lower speeds but now its maybe a different problem.

But what i will also try is to directly connect the NICs without switch

What it is really stupid is, the problem takes some days to appear

@deiruch
were this really SAS disks with problem? Once i had big speed troubles with WD SATA RAID disks on a HP SAS controller. Now i have also SATA disks.

[anton (staff)]

Try isolating your issue removing (replacing) components one-by-one.

1) NICs
2) Switch
3) Controller

In the mean time i switched NICs (now onboard iSCSI <-> PCI-X or PCIe i forgot, normal LAN), still the same.

At the moment i cannot bypass the PERC controller, because Windows is installed on the same disks (Windows no software RAID1 for OS). Another 2 disks i also cannot install because there is no place with "big" DAT drive:
http://www.disasterzone.net/blog/upload ... inside.png
I already discovered that the controller is a lot faster when write cache is enabled, which is no default. With that i had even lower speeds but now its maybe a different problem.

But what i will also try is to directly connect the NICs without switch

What it is really stupid is, the problem takes some days to appear

@deiruch
were this really SAS disks with problem? Once i had big speed troubles with WD SATA RAID disks on a HP SAS controller. Now i have also SATA disks.

[deiruch]

@deiruch
were this really SAS disks with problem? Once i had big speed troubles with WD SATA RAID disks on a HP SAS controller. Now i have also SATA disks.

Sorry, can't remember, was some time ago. Can't you connect a single SATA disk, just for testing?

[anton (staff)]

Better SSD...

@deiruch
were this really SAS disks with problem? Once i had big speed troubles with WD SATA RAID disks on a HP SAS controller. Now i have also SATA disks.

Sorry, can't remember, was some time ago. Can't you connect a single SATA disk, just for testing?

[danisoto]

I only have windows clients and ESX, so i ran iperf between windows vm and windows machine with starwind. Got around 550mbit/s. But how this will test iSCSI network?

Hi,

To check iSCSI with VSphere, try "iperf" for ESXi:
http://www.vm-help.com/forum/viewtopic. ... erf#p11541

Best check it with the real hosts (ESXi to SAN) using the real path (if you have multiple paths).

Regards!

[anton (staff)]

Thank you for suggestion! Great tool to check raw TCP performance.

I only have windows clients and ESX, so i ran iperf between windows vm and windows machine with starwind. Got around 550mbit/s. But how this will test iSCSI network?

Hi,

To check iSCSI with VSphere, try "iperf" for ESXi:
http://www.vm-help.com/forum/viewtopic. ... erf#p11541

Best check it with the real hosts (ESXi to SAN) using the real path (if you have multiple paths).

Regards!

[danisoto]

Thank you for suggestion! Great tool to check raw TCP performance.

You welcome!

[Anatoly (staff)]

ghost, we will wait for your update then.

[ghost]

reboot every week seems to fix it, probably problem with cache though

absolutely legit

[Anatoly (staff)]

Well, I`m glad that everything finished good!