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NFS High Availability Cluster

DISCUSSION Oded Maimon 3 participants 6 messages Jun 13, 2005

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#0 lore raw

Hi,

Is it possible to set an NFS HA cluster?

That means, that several servers will share the same disks in a SAN and will provide an NFS service for

all my other servers?

I need that when one NFS server will fail (or the network connection to it) then no server using the NFS will be affected and will continue to

work with one of the other NFS servers.

Is it possible?

Thanks,

Oded.

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#1 lore raw

To get started, see:

http://wiki.linux-ha.org/HaNFS

Quoted 20 lines · Oded Maimon

Hi,
=20
Is it possible to set an NFS HA cluster?
=20
That means, that several servers will share the same disks in a SAN and will provide an NFS service for
=20
all my other servers?
=20
=20
I need that when one NFS server will fail (or the network connection to it) then no server using the NFS will be affected and will continue to =20
work with one of the other NFS servers.
=20
=20
Is it possible?
=20
=20
Thanks,

Quoted 8 lines

=20
Oded.
=20
=20
=20
=20
-------------------------------------------------------
This SF.Net email is sponsored by: NEC IT Guy Games. How far can you sho=

tput

Quoted 1 line

a projector? How fast can you ride your desk chair down the office luge t=

rack?

Quoted 6 lines

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#2 lore raw
In reply to Oded Maimon

I'm told that the current generation of automounter should be able to failover readonly versions of the same data.

What we've been doing so far with linux, though, is to have a script that, instead of using fstab, instead traceroute's each of the replica servers and statically NFS mounts from the one that is up, and shows the lowest number of router hops.

The autofs failover should obviate reboots, at least to some extent.

The script I've described, which I'd be happy to share, makes it so endusers can just reboot to come up mounting from a different replica.

Quoted 35 lines · Oded Maimon

Hi,

Is it possible to set an NFS HA cluster?

That means, that several servers will share the same disks in a SAN and will provide an NFS service for

all my other servers?

I need that when one NFS server will fail (or the network connection to it) then no server using the NFS will be affected and will continue to

work with one of the other NFS servers.

Is it possible?

Thanks,

Oded.

-------------------------------------------------------
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_______________________________________________
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#3 lore raw

Hi,

I'm looking for a solution that will not make me reboot or even remount the file system (unless the remount is autmatically)...

what the reason that the automounter will do this only for read only data?

Thanks,

Oded.

Quoted 8 lines · Dan Stromberg

I'm told that the current generation of automounter should be able to failover readonly versions of the same data.

What we've been doing so far with linux, though, is to have a script that, instead of using fstab, instead traceroute's each of the replica servers and statically NFS mounts from the one that is up, and shows the lowest number of router hops.

Quoted 42 lines

The autofs failover should obviate reboots, at least to some extent.

The script I've described, which I'd be happy to share, makes it so endusers can just reboot to come up mounting from a different replica.

Quoted 34 lines · Oded Maimon

Hi,

Is it possible to set an NFS HA cluster?

That means, that several servers will share the same disks in a SAN and will provide an NFS service for

all my other servers?

I need that when one NFS server will fail (or the network connection to it) then no server using the NFS will be affected and will continue to

work with one of the other NFS servers.

Is it possible?

Thanks,

Oded.

-------------------------------------------------------
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_______________________________________________
NFS maillist - [email protected]
https://lists.sourceforge.net/lists/listinfo/nfs

-------------------------------------------------------
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_______________________________________________
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#4 lore raw

I've only heard of doing this with readonly data, but that's probably because multiple systems with the same "local filesystem" (in the SAN sense) is becoming more common recently.

If your SAN solution will resolve any concurrent-access problems you might have otherwise with multiple systems accessing the same filesystem blocks via the SAN, then you likely could have autofs do failover for readwrite (unless the automounter were arbitrarily restricted).

But to get this, it's entirely possible that you would have to use a special filesystem that is designed to handle multiple, "local", concurrent writers and readers, since to the OS, SAN blocks look a lot like local disk blocks, and you can't have two filesystems trying to access the same disk blocks concurrently, normally - otherwise, without automatic updates, you could end up with a corrupted filesystem.

Quoted 70 lines · Oded Maimon

Hi,

I'm looking for a solution that will not make me reboot or even remount the file system (unless the remount is autmatically)...

what the reason that the automounter will do this only for read only data?

Thanks,

Oded.

Quoted 53 lines · Dan Stromberg

I'm told that the current generation of automounter should be able to failover readonly versions of the same data.

What we've been doing so far with linux, though, is to have a script that, instead of using fstab, instead traceroute's each of the replica servers and statically NFS mounts from the one that is up, and shows the lowest number of router hops.

The autofs failover should obviate reboots, at least to some extent.

The script I've described, which I'd be happy to share, makes it so endusers can just reboot to come up mounting from a different replica.

Quoted 37 lines · Oded Maimon

Hi,

Is it possible to set an NFS HA cluster?

That means, that several servers will share the same disks in a SAN and will provide an NFS service for

all my other servers?

I need that when one NFS server will fail (or the network connection to it) then no server using the NFS will be affected and will continue to

work with one of the other NFS servers.

Is it possible?

Thanks,

Oded.

-------------------------------------------------------
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_______________________________________________
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#5 lore raw

Yes, you are right, i will have to use something like GFS on the NFS servers.

Quoted 9 lines · Dan Stromberg

I've only heard of doing this with readonly data, but that's probably because multiple systems with the same "local filesystem" (in the SAN sense) is becoming more common recently.

If your SAN solution will resolve any concurrent-access problems you might have otherwise with multiple systems accessing the same filesystem blocks via the SAN, then you likely could have autofs do failover for readwrite (unless the automounter were arbitrarily restricted).

Quoted 81 lines

But to get this, it's entirely possible that you would have to use a special filesystem that is designed to handle multiple, "local", concurrent writers and readers, since to the OS, SAN blocks look a lot like local disk blocks, and you can't have two filesystems trying to access the same disk blocks concurrently, normally - otherwise, without automatic updates, you could end up with a corrupted filesystem.

Quoted 71 lines · Oded Maimon

Hi,

I'm looking for a solution that will not make me reboot or even remount the file system (unless the remount is autmatically)...

what the reason that the automounter will do this only for read only data?

Thanks,

Oded.

Quoted 54 lines · Dan Stromberg

I'm told that the current generation of automounter should be able to failover readonly versions of the same data.

What we've been doing so far with linux, though, is to have a script that, instead of using fstab, instead traceroute's each of the replica servers and statically NFS mounts from the one that is up, and shows the lowest number of router hops.

The autofs failover should obviate reboots, at least to some extent.

The script I've described, which I'd be happy to share, makes it so endusers can just reboot to come up mounting from a different replica.

Quoted 36 lines · Oded Maimon

Hi,

Is it possible to set an NFS HA cluster?

That means, that several servers will share the same disks in a SAN and will provide an NFS service for

all my other servers?

I need that when one NFS server will fail (or the network connection to it) then no server using the NFS will be affected and will continue to

work with one of the other NFS servers.

Is it possible?

Thanks,

Oded.

-------------------------------------------------------
This SF.Net email is sponsored by: NEC IT Guy Games. How far can you shotput
a projector? How fast can you ride your desk chair down the office luge track?
If you want to score the big prize, get to know the little guy. Play to win an NEC 61" plasma display: http://www.necitguy.com/?r=20
_______________________________________________
NFS maillist - [email protected]
https://lists.sourceforge.net/lists/listinfo/nfs

-------------------------------------------------------
This SF.Net email is sponsored by: NEC IT Guy Games. How far can you shotput
a projector? How fast can you ride your desk chair down the office luge track?
If you want to score the big prize, get to know the little guy. Play to win an NEC 61" plasma display: http://www.necitguy.com/?r=20
_______________________________________________
NFS maillist - [email protected]
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