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aaronb123
Contributor
Contributor

Storage Question: FC and iSCSI Datastores

Hi,

I have a storage question. My environment consists of multiple clusters all pointing to a common SAN. Some clusters are connected to the SAN via FC and some via iSCSI.

Many of the Datastores are being simultaneously accessed by both iSCSI and FC connected ESXes. Is this a bad practice? is it even supported? Should I be segregating the storage based on connecting medium?

Thanks for the info

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5 Replies
AntonVZhbankov
Immortal
Immortal

If you present the same LUN via FC and iSCSI simultaneously - that's bad practice.


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mcowger
Immortal
Immortal

No its not - this works fine with most storage and some vendors even recommend it.

Can you show a document detailing the problems one would encounter?






--Matt

VCP, vExpert, Unix Geek

--Matt VCDX #52 blog.cowger.us
aaronb123
Contributor
Contributor

I ask because I've experienced iSCSI reservation issues that have lead to HOSTD related issues.

On a iSCSI host its manifested as HOSTD crash and lost all connectivity to storage from the esx host. Only remedy is to "reboot -f"

On FC (happened the first time today, ESX became disconnected from vCenter but storage was still online as did the VMs. Remedy was to restart HOSTD service.

From the vmwarning log:

Oct 26 12:14:53 ESX_Srv_Name vmkernel: 4:14:23:04.419 cpu4:1047)WARNING: SCSI: 119: Failing I/O due to too many reservation conflicts

Oct 26 12:58:37 ESX_Srv_Name vmkernel: 4:15:06:47.933 cpu6:1049)WARNING: SCSI: 119: Failing I/O due to too many reservation conflicts

Oct 26 13:30:46 ESX_Srv_Name vmkernel: 4:15:38:57.209 cpu9:1048)WARNING: SCSI: 119: Failing I/O due to too many reservation conflicts

Oct 26 14:24:32 ESX_Srv_Name vmkernel: 4:16:32:43.282 cpu11:1048)WARNING: SCSI: 119: Failing I/O due to too many reservation conflicts

Oct 26 20:11:46 ESX_Srv_Name vmkernel: 4:22:19:56.325 cpu5:1047)WARNING: SCSI: 119: Failing I/O due to too many reservation conflicts

Oct 26 20:11:46 ESX_Srv_Name vmkernel: 4:22:19:56.331 cpu5:1047)WARNING: FS3: 2949: reservation error: SCSI reservation conflict

Oct 26 20:11:46 ESX_Srv_Name vmkernel: 4:22:19:56.338 cpu5:1047)WARNING: FS3: 3406: Failed with bad0022

Oct 26 20:11:46 ESX_Srv_Name vmkernel: 4:22:19:56.352 cpu5:1047)WARNING: Fil3: 1787: Failed to reserve volume f530 28 1

I'm going to disable the HP agents that relate to storage, but this recent issue has me worried.

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TobiasKracht
Expert
Expert

First try to find out reason of SCSI reservation conflict

StarWind Software R&D

StarWind Software R&D http://www.starwindsoftware.com
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mcowger
Immortal
Immortal

Tobias is right - this has less to do with access method and more to do with your storage keeping up.






--Matt

VCP, vExpert, Unix Geek

--Matt VCDX #52 blog.cowger.us
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