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  • 1.  Problem with multi connections on iSCSI Target

    Posted Jul 24, 2013 06:12 PM

    Hi there,

    i'm running into a problem with my Synology DiskStation and vSphere 5.1.

    I created a LUN on my Synology and set up an iSCSI Target with multiple connections allowed!

    While having only one ESXi host connected it runs fine. As soon as i connect a second host i'll get "Failed to log into NFC Server".

    I double cheked all the recommendations from this forum (for example DNS, the well known KB to fix this problem,...) - nothing help.

    If i disconnect the host and run just a single connection to the fileserver it's fine again...

    I read a hint on the synology box "Be sure to run a cluster filesystem on your device while allowing multi connections..."

    But a iSCSI-datastore is VMFS and that is a cluster fs, isn't it?

    May be a stupid question but it's my first lab build with an ESXi-Cluster and a dedicated Fileserver...



  • 2.  RE: Problem with multi connections on iSCSI Target

    Posted Aug 02, 2013 02:11 AM

    You can't share one iSCSI target to multiple clients (servers, esx, xen etc.) except they are running as cluster.



  • 3.  RE: Problem with multi connections on iSCSI Target

    Posted Aug 02, 2013 05:38 AM

    Hi,

    Of course, you can share the same LUN to multiple host in the same cluster.

    Did you try to create a new LUN and check if you can add it? Maybe your LUN is corrupted.

    Did you check any events from the Synology when you are attempting to connect?

    Regards,

    Julien.



  • 4.  RE: Problem with multi connections on iSCSI Target

    Posted Aug 15, 2013 04:45 PM

    I was trying this out in my lab some time back and I too ran into the similar situation. check this http://forum.gotzu.com/showthread.php?tid=76

    I figured out the way to decieve both host by configuring multiple IPs to iSCSI network adaptor. Then while adding iSCSI target to two hosts assign one IP for one host and second IP for the second host. iSCSI initiator etc. will remain same. Try this if it is helpful.



  • 5.  RE: Problem with multi connections on iSCSI Target

    Posted Sep 06, 2013 04:00 AM

    You certainly can not connect to the iSCSI target with full access from two clients except clients in cluster..This can damage the disk....



  • 6.  RE: Problem with multi connections on iSCSI Target

    Posted Sep 08, 2013 01:58 PM

    Of course you can do it! Just a few options:

    1) You should use cluster-aware file system to format the volume. GlusterFS, OCFS2, VMFS, SFS, MelioFS etc. They keep a

    2) Using non-cluster aware file system would require you to use an external distributed lock. For say NTFS and HFS you can use MetaSAN from Tiger Technologies.

    3) Use cluster-aware application doing arbitration on it's own. Say Hyper-V will keep one node access in a block mode to NTFS and other nodes will have redirected

    access thru the SMB file share (mix of the block and file access). VMware has clustered file system (VMFS) and Microsoft still is playing games with a good old NTFS :smileyhappy:

    Generally speaking the topic raises since FC and shared parallel SCSI all the time. You can read more there:

    Trying to be clear on this - use iSCSI instead of SMB

    (StarWind discussion forum but the topic itself has nothing to do with the company itself, it's the same for all the SANs) and here:

    http://community.spiceworks.com/topic/376034-multi-hyper-v-host-sharing-one-storage-volume

    (also about Hyper-V in general but the topic is the same including all the concepts and options).

    Good luck :smileyhappy:

    --

    Hi there,

    i'm running into a problem with my Synology DiskStation and vSphere 5.1.

    I created a LUN on my Synology and set up an iSCSI Target with multiple connections allowed!

    While having only one ESXi host connected it runs fine. As soon as i connect a second host i'll get "Failed to log into NFC Server".

    I double cheked all the recommendations from this forum (for example DNS, the well known KB to fix this problem,...) - nothing help.

    If i disconnect the host and run just a single connection to the fileserver it's fine again...

    I read a hint on the synology box "Be sure to run a cluster filesystem on your device while allowing multi connections..."

    But a iSCSI-datastore is VMFS and that is a cluster fs, isn't it?

    May be a stupid question but it's my first lab build with an ESXi-Cluster and a dedicated Fileserver...



  • 7.  RE: Problem with multi connections on iSCSI Target

    Posted Nov 18, 2014 06:18 AM

    Hi all,

    I'm replying because I have the same setup as the original poster: ESXi 5.1 hosts with a Synology, using iSCSI.

    This is not an elegant answer--and should certainly not be used in a production environment--(but since it's a Synology, I'm guessing this situation is a home lab scenario like mine is).

    I had an ESXi 5.1 host crash hard, no configs changed on it at all, but when I brought it back online it would not reconnect to the Synology iSCSI target.  I tried changing network configurations on the host, different bindings, removed and readded the software iSCSI adapter...nothing worked.

    Finally, after determining that it was not a configuration issue--nor had any hardware gone bad, (thankfully!), I powered off the Synology, waited a minute, and brought it back online.  When it was back online, rescanning the storage adapters on each host made them see the iSCSI storage again!

    I couldn't say for sure why this happened in the first place, but I suspect an outdated DSM version on the Synology.  I'm running DSM 4.1-2668, and the latest version as of this post is 4.3-3827.  Hopefully, the update is a more permanent fix or preventative measure.

    HTH!