Date: Fri, 20 Jul 2012 15:02:08 +0200 From: dennis berger <db@nipsi.de> To: John <jwd@freebsd.org> Cc: freebsd-fs@freebsd.org Subject: Re: ISCSI on zvols with two maschines. What needs to be done? Message-ID: <F17CCAC7-97A6-406A-B8A8-087AFC267368@nipsi.de> In-Reply-To: <20120720123255.GA56250@FreeBSD.org> References: <7FE7A5F3-53FF-4508-A3D6-562E8FA9764D@nipsi.de> <20120720123255.GA56250@FreeBSD.org>
next in thread | previous in thread | raw e-mail | index | archive | help
Hi John, see inline. Am 20.07.2012 um 14:32 schrieb John: > Hi Dennis, >=20 > ----- dennis berger's Original Message ----- >> Hi folks, >>=20 >> The following question often comes to me, when I speak to my = customers. >>=20 >> Is it possible to attach two systems to the same storage array using = shared SAS and use istgt + zfs to provide=20 >> a reliable ISCSI target. This could be active/passive or later = active/active. In case it's not possible, what needs to be done? >>=20 >> The questions that came into my mind. >>=20 >> Can I connect two freebsd to the storage and boot them up? Just that = both systems would see the physical devices.=20 >=20 > Yes, please see: >=20 > http://people.freebsd.org/~jwd/zfsnfsserver.jpg This is exactly how I would like to use it. >=20 > for a possible diagram. Dual path all the shelves and use gmultipath = to > access them. Use 9-stable. OK. And with new multipath code. I remember I read something in = quarterly reports=85 >=20 > Make sure each host is dual homed and a client (initiator) can access > the target with dual pathing, one connection over each network path. >=20 OK but it's still accessing one target right. >> Can I start ZFS on both systems without writing on it? I would like = to use just block devices for ISCSI. Is everything still consistent? >=20 > You can start ZFS on both systems and import different pools. The same = pool > cannot be imported on two different systems (you can, you won't be = happy). >=20 Ahh you mean to create a separate zfs pool with the different devices = names according to multipath. Which in in essence are the same physical = devices?! PoolA with da0 and da2=20 PoolB with da1 and da3 =20 da0 and da1 are the same device but different paths? But where is the difference?! Maybe I don't understand exactly why 2 = pools >> Does starting ZFS up already writing some sort of meta data to the = physical devices?! >=20 > Yes, others would know better than I. OK >=20 >> Can I start istgt on both systems without actually using the istgt on = one system?! Then CARP would be enough, wouldn't it. >=20 > You start istgt on both systems handing out luns from the two = different > pools you have mounted on each head. Hint, put your istgt configs for > each pool in each pool. >=20 > Using CARP/DEVD and some shell code, if head A dies, you import the > failing heads pool on the other system and bring istgt up. CARP = handles > the IP address switch over. Do I need to zfs import?!=20 -dennis >=20 >> Or in case of active/active extend istgt to communicate with the = other istgt to not hand out a device twice?=20 >=20 > Not sure I'd want to expend the effort here. Just an opinion. >=20 > Hope this helps. >=20 > -John >=20 >> Best, >> -dennis >=20 Dipl.-Inform. (FH) Dennis Berger email: db@bsdsystems.de mobile: +491791231509 fon: +494054001817
Want to link to this message? Use this URL: <https://mail-archive.FreeBSD.org/cgi/mid.cgi?F17CCAC7-97A6-406A-B8A8-087AFC267368>