Limit max concurrent sessions

Limit max concurrent sessions

[Gionatan Danti]

Hi all,
I would like to understand if, and how to, limit the maximum number of 
simultaneous connections to a specific LUN, both with the old iSCSI 
stack (tgtadmin and friends) and the new one (targetcli and the likes).

I am exporting a LUN with a general purpose filesystem (non cluster 
aware) and I would be 100% sure that only a single machine at a time can 
mount it.

At the moment, I protected the iSCSI LUN with both an IP-based access 
list and a username/password combo, but hard limiting the maximum number 
of connections opened against it to 1 (one) would be a nice thing...

As I have mixed RHEL 6 and 7 environment, I am interested in how to do 
that on both the old and new iSCSI stack.

Thank you,
regards.

-- 
Danti Gionatan
Supporto Tecnico
Assyoma S.r.l. - www.assyoma.it
email: g.danti@assyoma.it - info@assyoma.it
GPG public key ID: FF5F32A8

Re: Limit max concurrent sessions

[Gionatan Danti]

Hi all,
anyone with some ideas / infos ?

Thanks.

On 06/05/15 17:36, Gionatan Danti wrote:
> Hi all,
> I would like to understand if, and how to, limit the maximum number of
> simultaneous connections to a specific LUN, both with the old iSCSI
> stack (tgtadmin and friends) and the new one (targetcli and the likes).
>
> I am exporting a LUN with a general purpose filesystem (non cluster
> aware) and I would be 100% sure that only a single machine at a time can
> mount it.
>
> At the moment, I protected the iSCSI LUN with both an IP-based access
> list and a username/password combo, but hard limiting the maximum number
> of connections opened against it to 1 (one) would be a nice thing...
>
> As I have mixed RHEL 6 and 7 environment, I am interested in how to do
> that on both the old and new iSCSI stack.
>
> Thank you,
> regards.
>

-- 
Danti Gionatan
Supporto Tecnico
Assyoma S.r.l. - www.assyoma.it
email: g.danti@assyoma.it - info@assyoma.it
GPG public key ID: FF5F32A8

Re: Limit max concurrent sessions

[Emmanuel Florac]

Le Wed, 23 Sep 2015 16:20:01 +0200
Gionatan Danti <g.danti@assyoma.it> écrivait:

> Hi all,
> anyone with some ideas / infos ?
> 
> Thanks.
> 
> On 06/05/15 17:36, Gionatan Danti wrote:
> > Hi all,
> > I would like to understand if, and how to, limit the maximum number
> > of simultaneous connections to a specific LUN, both with the old
> > iSCSI stack (tgtadmin and friends) and the new one (targetcli and
> > the likes).
> >
> > I am exporting a LUN with a general purpose filesystem (non cluster
> > aware) and I would be 100% sure that only a single machine at a
> > time can mount it.
> >
> > At the moment, I protected the iSCSI LUN with both an IP-based
> > access list and a username/password combo, but hard limiting the
> > maximum number of connections opened against it to 1 (one) would be
> > a nice thing...
> >
> > As I have mixed RHEL 6 and 7 environment, I am interested in how to
> > do that on both the old and new iSCSI stack.
> >

Use XFS. XFS won't let you mount it several time on different machines
without various "force" options.
Alternatively, use a cluster-aware FS like ocfs2. Ocfs2 is quite easy
to set up.

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Re: Limit max concurrent sessions

[Gionatan Danti]

Il 23-09-2015 17:18 Emmanuel Florac ha scritto:
> 
> Use XFS. XFS won't let you mount it several time on different machines
> without various "force" options.
> Alternatively, use a cluster-aware FS like ocfs2. Ocfs2 is quite easy
> to set up.

Thank you for the suggestion.
Unfortunately, due to specific requirements I must use EXT4.

So, there is no methods to limit concurrent connections?
Thanks.

-- 
Danti Gionatan
Supporto Tecnico
Assyoma S.r.l. - www.assyoma.it
email: g.danti@assyoma.it - info@assyoma.it
GPG public key ID: FF5F32A8

Re: Limit max concurrent sessions

[Emmanuel Florac]

Le Sun, 27 Sep 2015 12:28:41 +0200
Gionatan Danti <g.danti@assyoma.it> écrivait:

> Il 23-09-2015 17:18 Emmanuel Florac ha scritto:
> > 
> > Use XFS. XFS won't let you mount it several time on different
> > machines without various "force" options.
> > Alternatively, use a cluster-aware FS like ocfs2. Ocfs2 is quite
> > easy to set up.
> 
> Thank you for the suggestion.
> Unfortunately, due to specific requirements I must use EXT4.
> 
> So, there is no methods to limit concurrent connections?
> Thanks.

Not that I know of using LIO. However, using ietd you can use the
MaxSession parameter to limit the number of concurrent sessions. 

-- 
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Emmanuel Florac     |   Direction technique
                    |   Intellique
                    |	<eflorac@intellique.com>
                    |   +33 1 78 94 84 02
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Re: Limit max concurrent sessions

[Bernd Schubert]

On 09/27/2015 12:28 PM, Gionatan Danti wrote:
> Il 23-09-2015 17:18 Emmanuel Florac ha scritto:
>>
>> Use XFS. XFS won't let you mount it several time on different machines
>> without various "force" options.
>> Alternatively, use a cluster-aware FS like ocfs2. Ocfs2 is quite easy
>> to set up.
> 
> Thank you for the suggestion.
> Unfortunately, due to specific requirements I must use EXT4.

ext4 has MMP support (multiple mount protection), you can enable it with
tune2fs.

Cheers,
Bernd