[Linux-cluster] Re: If I have 5 GNBD server?
Michael
mikore.li at gmail.com
Sun Aug 28 16:39:53 UTC 2005
On 8/27/05, brianu <brianu at silvercash.com> wrote:
>
>
>
> Hello all,
>
>
>
> This is a question I have basically been asking, the question on why you
> would want to do it is failover, the docs at
> http://sourceware.org/cluster/gnbd/gnbd_usage.txt state
> that dm-multipath is an option for gnbd, and documents elsewhere also
> indicate that GNBD can be configured as a redundancy, yet I cannot find any
> documentation on how to configure it.
>
>
>
> If using LVM to make a volume of imported gnbds is not the answer for
> redundancy can anyone suggest a method that is? Im not opposed to using any
> other resource of cluster or GFS but I would really like to implement a
> redundant solution, ( gnbd, gulm, etc.).
>
Hi, Brianu, maybe LVM + md + gnbd should be one of the solution for
redundancy, for example, you have 2 gnbd servers, each one exports 1
disk. Then, the steps should be:
1. create a RAID-1 /dev/md0 on GFS client with imported 2 gnbd block devices.
2. use LVM create /dev/vg0 on top of them.
3. mkfs_gfs on /dev/vg0.
I haven't tried this configuration, theoretically, it should work.
Thanks,
Michael
>
>
>
>
> Does anyone has an example of a redundant solution for a cluster/gfs
> filesystem i.e ( gnbd, gulm etc) ?
>
>
>
> Regards,
>
>
>
> Brian
>
>
>
> Message: 9
>
> Date: Fri, 26 Aug 2005 16:33:51 +0700
>
> From: "Fajar A. Nugraha" <fajar at telkom.co.id>
>
> Subject: Re: [Linux-cluster] Re: If I have 5 GNBD server?
>
> To: linux clustering <linux-cluster at redhat.com>
>
> Message-ID: <430EE1FF.6050505 at telkom.co.id>
>
> Content-Type: text/plain; charset=ISO-8859-1; format=flowed
>
>
>
> Michael wrote:
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>
>
> >Can anyone answer my question?
>
> >
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> >
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> >
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> I don't think LVM cares what kind of storage it uses, as long as it's a
>
> block device.
>
> So theoretically, you can mix local disc, FC storage, GNBD, and ATOE and
>
> combine them using LVM. You might run into performance issues (GNBD are
>
> slower than FC disks) and startup issues (LVM has to start after cluster
>
> and gnbd-import successfuly start), but it should be possible.
>
>
>
> The real question is WHY you want to do that.
>
> AFAIK, if you combine 5 gnbd from 5 gnbd servers into one LVM, and you
>
> are accessing a volume on that volume group, and one of the gnbd server
>
> dies (or hangs), gnbd import will wait forever until that server is back
>
> up. So you'll have five more single-point-of-failures.
>
>
>
> Regards,
>
>
>
> Fajar
>
>
>
> >On 8/26/05, Michael <mikore.li at gmail.com> wrote:
>
> >
>
> >
>
> >>Hi,
>
> >>
>
> >>If I have 5 gnbd servers in the network, each one export 1 block
>
> >>device, can I import all gnbd devices on each gfs client, and use lvm
>
> >>to manage them as 1 shared pool, then mkfs_gfs on it?
>
> >>
>
> >>Thanks,
>
> >>
>
> >>Michael
>
> >>
>
> >>
>
> >>
>
> >
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> >
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> >
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> Brian Urrutia
>
> System Administrator
>
> Price Communications Inc.
>
> There are 10 types of people in this world,
> those who understand binary and those who don't.
>
>
>
> --
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>
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