Date: Wed, 01 Oct 2014 15:52:16 +0200 From: InterNetX - Juergen Gotteswinter <jg@internetx.com> To: George Kontostanos <gkontos.mail@gmail.com>, freebsd-fs@freebsd.org Subject: Re: HAST with broken HDD Message-ID: <542C0710.3020402@internetx.com> In-Reply-To: <CA%2BdUSyoEcPdJ1hdR3k1vNROFG7p1kN0HB5S2a_0gYhiV75OLAw@mail.gmail.com> References: <542BC135.1070906@Skynet.be> <542BDDB3.8080805@internetx.com> <CA%2BdUSypO8xTR3sh_KSL9c9FLxbGH%2BbTR9-gPdcCVd%2Bt0UgUF-g@mail.gmail.com> <542BF853.3040604@internetx.com> <CA%2BdUSyp4vMB_qUeqHgXNz2FiQbWzh8MjOEFYw%2BURcN4gUq69nw@mail.gmail.com> <542C019E.2080702@internetx.com> <CA%2BdUSyoEcPdJ1hdR3k1vNROFG7p1kN0HB5S2a_0gYhiV75OLAw@mail.gmail.com>
next in thread | previous in thread | raw e-mail | index | archive | help
Am 01.10.2014 um 15:49 schrieb George Kontostanos: > On Wed, Oct 1, 2014 at 4:29 PM, InterNetX - Juergen Gotteswinter > <jg@internetx.com <mailto:jg@internetx.com>> wrote: > > Am 01.10.2014 um 15:06 schrieb George Kontostanos: > > > > > > On Wed, Oct 1, 2014 at 3:49 PM, InterNetX - Juergen Gotteswinter > > <jg@internetx.com <mailto:jg@internetx.com> <mailto:jg@internetx.com > <mailto:jg@internetx.com>>> wrote: > > > > Am 01.10.2014 um 14:28 schrieb George Kontostanos: > > > > > > On Wed, Oct 1, 2014 at 1:55 PM, InterNetX - Juergen Gotteswinter > > > <jg@internetx.com <mailto:jg@internetx.com> <mailto:jg@internetx.com > <mailto:jg@internetx.com>> > > <mailto:jg@internetx.com <mailto:jg@internetx.com> <mailto:jg@internetx.com > <mailto:jg@internetx.com>>>> wrote: > > > > > > Am 01.10.2014 um 10:54 schrieb JF-Bogaerts: > > > > Hello, > > > > I'm preparing a HA NAS solution using HAST. > > > > I'm wondering what will happen if one of disks of the > > primary node will > > > > fail or become erratic. > > > > > > > > Thx, > > > > Jean-François Bogaerts > > > > > > nothing. if you are using zfs on top of hast zfs wont even > > take notice > > > about the disk failure. > > > > > > as long as the write operation was sucessfull on one of the 2 > > nodes, > > > hast doesnt notify the ontop layers about io errors. > > > > > > interesting concept, took me some time to deal with this. > > > > > > > > > Are you saying that the pool will appear to be optimal even with a bad > > > drive? > > > > > > > > > > https://forums.freebsd.org/viewtopic.php?&t=24786 > > > > > > > > It appears that this is actually the case. And it is very disturbing, > > meaning that a drive failure goes unnoticed. In my case I completely > > removed the second disk on the primary node and a zpool status showed > > absolutely no problem. Scrubbing the pool began resilvering which > > indicates that there is actually something wrong! > > > right. lets go further and think how zfs works regarding direct hardware > / disk access. theres a layer between which always says ey, everthing is > fine. no more need for pool scrubbing, since hastd wont tell if anything > is wrong :D > > > Correct, ZFS needs direct access and any layer in between might end up a > disaster!!! > > Which means that practically HAST should only be used in UFS > environments backed by a hardware controller. In that case, HAST will > not notice again anything (unless you loose the controller) but at least > you will know that you need to replace a disk, by monitoring the > controller status. > imho this should be included at least as a notice/warning in the hastd manpage, afaik theres no real warning about such problems with the hastd/zfs combo. but lots of howtos are out there describing exactly such setups. sad, since the comparable piece on linux - drbd - is handling io errors fine. the upper layers get notified like it should be imho
Want to link to this message? Use this URL: <https://mail-archive.FreeBSD.org/cgi/mid.cgi?542C0710.3020402>