[sheepdog-users] Sheepdog Block Device SPOF and kernel log size

[Hitoshi Mitake]

At Fri, 10 Jul 2015 01:19:05 +0200,
Michał Chybowski wrote:
> 
> W dniu 09.07.2015 o 17:29, Hitoshi Mitake pisze:
> > At Thu, 09 Jul 2015 17:15:08 +0200,
> > Michał Chybowski wrote:
> >> Hi
> >>
> >> I've set up a Sheepdog cluster on 3 machines (as data hosts) and 1
> >> "client" machine, on which Sheepdog Block Devices will be used. I'd like
> >> to associate them with more than one sheep daemon - is there any
> >> possible way of doing this? I want to avoid death of services using SBD
> >>
> >> Also, my kern.log (using Debian wheezy) is growing extremely fast due to
> >> SBD module logging almost every action. How can I avoid this?
> > If you can use iSCSI interface of sheepdog, you can avoid SPOF because
> > it supports multipath:
> > https://github.com/sheepdog/sheepdog/wiki/General-protocol-support-(iSCSI-and-NBD)
> Ok, I'm sure I'll try this but is there any multipath config file or so 
> for SBD? I'd love to test this out but at the moment only thing I get 
> from multipath is:
> 
> root at compute1:~# multipath -p failover /dev/sbd0
> Jul 10 00:43:22 | DM message failed [fail_if_no_path]
> 
> which with -v3 gives more information:
> 
> Jul 10 00:44:09 | sbd0: ownership set to lolek
> Jul 10 00:44:09 | sbd0: not found in pathvec
> Jul 10 00:44:09 | sbd0: mask = 0xc
> Jul 10 00:44:09 | sbd0: get_state
> Jul 10 00:44:09 | sbd0: path checker = directio (internal default)
> Jul 10 00:44:09 | sbd0: path inaccessible
> 
> and with -v4:
> Jul 10 01:03:50 | Discover device /sys/block/sbd0
> Jul 10 01:03:50 | path /sys/block/sbd0/device not present
> Jul 10 01:03:50 | Discover device /sys/block/sbd1
> Jul 10 01:03:50 | path /sys/block/sbd1/device not present
> 
> I hope there is some way to utilize SBD instead of using iSCSI.

iSCSI multipath requires coherence protocol of in memory inode
object. Supporting it in sbd is costly so I suggest to use iSCSI if it
is not a problem for you.

Thanks,
Hitoshi

> 
> >
> > Recent talk of Ishizaki-san has a brief description about the
> > multipath mechanism:
> > http://events.linuxfoundation.jp/sites/events/files/slides/COJ2015_Sheepdog_20150604.pdf
> >
> > I think you are using linux as a client. We are testing the iSCSI
> > feature with open-iscsi initiator. Therefore you would be able to use
> > the initiator in your environment.
> >
> > # the description of multipath setup is still under construction. I'll
> > # prepare it later. tests/functional/097 has a way of multipath setup
> >
> > Thanks,
> > Hitoshi
> >
> >> -- 
> >> Reards
> >> Michał Chybowski
> >> Tiktalik.com
> >>
> >> -- 
> >> sheepdog-users mailing lists
> >> sheepdog-users at lists.wpkg.org
> >> https://lists.wpkg.org/mailman/listinfo/sheepdog-users
> 
> Thanks
> Michał Chybowski
> Tiktalik.com
> 
> 
>