Concurrent mount of XFS over SAN
Is there a way to prevent and/or detect concurrent mount of same XFS SAN-based partition from several nodes?
I had to fsck a filesystem losing some data after two nodes happily mounted a filesystem from same SAN-based partition at the same time and wrote into it.
Thanks!
--alan
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Quoted 7 lines · Heilige Gheist
Is there a way to prevent and/or detect concurrent mount of same XFS SAN-based partition from several nodes?
I had to fsck a filesystem losing some data after two nodes happily mounted a filesystem from same SAN-based partition at the same time and wrote into it.
Thanks!
Quoted 8 lines
--alan
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I think that the generally accepted way is to zone at the switch or the storage array.
Signature · 4 lines
Dave Lloyd Test Engineer, Exegy, Inc. 314.450.5342 [email protected]
Dave,
That's 100% correct assuming you prohibit a shared access between the nodes. I didn't point out that we're dealing with filesystem failover setup.
It's obvious that I can always fall back to the inter-node heart-beat to ensure that only one node is mounting the filesystem. I'm just wondering if there's any facility or accepted practice to enforce it.
Thanks,
Alan
Quoted 20 lines · --- Dave Lloyd
Quoted 1 line · Heilige Gheist
Is there a way to prevent and/or detect concurrent mount of same
XFS
Quoted 2 lines
SAN-based partition from several nodes?
I had to fsck a filesystem losing some data after two nodeshappily
Quoted 1 line
mounted a filesystem from same SAN-based partition at the same
time and
Quoted 11 lines
wrote into it.
Thanks!--alan
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Quoted 12 lines
I think that the generally accepted way is to zone at the switch or the
storage array.Signature · 4 lines
Dave Lloyd Test Engineer, Exegy, Inc. 314.450.5342 [email protected]
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Quoted 4 lines · Heilige Gheist
It's obvious that I can always fall back to the inter-node heart-beat to ensure that only one node is mounting the filesystem. I'm just wondering if there's any facility or accepted practice to enforce it.
STONITH (Shoot The Other Node In The Head) trough smart power switches or management adapters in the node.
SCSI reserve/release ... No idea how reliable this is on a SAN, but the ServeRAID-version works great. http://www.linux-ha.org/ServeRAID
Export the volume group, or scsi device on the first node, before importing/attaching it on the second .. Probably best to use together with STONITH, in case the first node fails on unmounting/exporting.
BTW: I think XFS on IRIX had the owning node name in the file system header, and only would allow this node to mount the fs. But I can't find this now... Maybe it's gone, or maybe it was in xlv.. ?
-jf
afaik, the node was stored in xlv, which was an extra option in IRIX, ( extra license) but this could later be used in CXFS which allows multiple machines to mount the same FS read write from a SAN, made for clusters, HA and HPC...
knowledge of the node "owning" the device was in there for protection. but can be overridden with an xlv command.
kind regards, Kris
Quoted 28 lines · Jan-Frode Myklebust
Quoted 5 lines · Heilige Gheist
It's obvious that I can always fall back to the inter-node heart-beat to ensure that only one node is mounting the filesystem. I'm just wondering if there's any facility or accepted practice to enforce it.
STONITH (Shoot The Other Node In The Head) trough smart power switches or management adapters in the node.
SCSI reserve/release ... No idea how reliable this is on a SAN, but the ServeRAID-version works great. http://www.linux-ha.org/ServeRAID
Export the volume group, or scsi device on the first node, before importing/attaching it on the second .. Probably best to use together with STONITH, in case the first node fails on unmounting/exporting.
BTW: I think XFS on IRIX had the owning node name in the file system header, and only would allow this node to mount the fs. But I can't find this now... Maybe it's gone, or maybe it was in xlv.. ?
-jf
Maybe off topic meanwhile, but both Irix volume managers xlv and xvm have the owner stored in the header. Xvm also has an understanding of a cluster owning the volume, which is required for cxfs.
In a failover environment you absolutely have to make sure the failed machine really has no more access to the volume, preferably by fencing the FC switch ports, before you mount it on the standby system. STONITH implementations also work, but still two machines have to agree on the ownership when the failed machine comes up again.
Cheers
Sebastian
Quoted 2 lines
-----Original Message-----
From: [email protected] [mailto:[email protected]] On Behalf
Of
Quoted 7 lines
kris buggenhout
Sent: Montag, 7. August 2006 13:02
To: Jan-Frode Myklebust
Cc: [email protected]
Subject: Re: Concurrent mount of XFS over SANafaik, the node was stored in xlv, which was an extra option in IRIX,
(
Quoted 4 lines
extra license) but this could later be used in CXFS which allows multiple machines to mount the same FS read write from a SAN, made for clusters, HA and HPC...
Quoted 9 lines
knowledge of the node "owning" the device was in there for protection. but can be overridden with an xlv command.
kind regards, Kris
Quoted 3 lines · Jan-Frode Myklebust
Quoted 1 line · Heilige Gheist
It's obvious that I can always fall back to the inter-node
heart-beat
Quoted 6 lines
Quoted 6 lines
Quoted 4 lines
to ensure that only one node is mounting the filesystem. I'm just wondering if there's any facility or accepted practice to enforce it.
STONITH (Shoot The Other Node In The Head) trough smart power
switches
Quoted 3 lines
Quoted 3 lines
or management adapters in the node.
SCSI reserve/release ... No idea how reliable this is on a SAN, but
the
Quoted 4 lines
Quoted 4 lines
ServeRAID-version works great. http://www.linux-ha.org/ServeRAID
Export the volume group, or scsi device on the first node, before importing/attaching it on the second .. Probably best to use
together
Quoted 5 lines
Quoted 3 lines
with STONITH, in case the first node fails on unmounting/exporting.
BTW: I think XFS on IRIX had the owning node name in the file system
header,
Quoted 1 line
and only would allow this node to mount the fs. But I can't find
this
Quoted 11 lines
now...
Quoted 9 lines
Maybe it's gone, or maybe it was in xlv.. ?
-jf