On Thu, 2008-05-01 at 21:31 -0500, David Lethe wrote: > In a perfect world, my expectation is that sharing a disk is safe and > even a reasonable thing to do. The shared disk is effectively a range of > addressable blocks in the same way an individual disk or even a hardware > RAID LUN is a range of blocks. From this limited perspective, the only > penalty is performance related, assuming you don't mind having to > explain yourself to an IT supervisor somewhere in your company. > > However, consider what COULD happen in event of a drive failure, either > with the shared or an unshared disk. What are the odds all of the > failure scenarios have been tested for all ATA and SCSI command sets; > with threaded I/Os pending; with dirty cache; bus resets when hardware > dies; etc... ? > > The odds are zero. Look how many problems people post to the thread on > a weekly basis where people lose their data when md rebuilds go bad with > non-shared disks. Why make the problem worse? What? are you saying linux md is unreliable?! in other words, would i be safer to run rsync every day to my other disk, and run in non-raid mode?! > > -----Original Message----- > From: linux-raid-owner@xxxxxxxxxxxxxxx > [mailto:linux-raid-owner@xxxxxxxxxxxxxxx] On Behalf Of Alex Davis > Sent: Thursday, May 01, 2008 8:52 PM > To: Justin Piszcz; Kasper Sandberg > Cc: linux-raid@xxxxxxxxxxxxxxx; linux-kernel@xxxxxxxxxxxxxxx > Subject: Re: Sharing disks amoung multiple software RAIDs > > --- On Thu, 5/1/08, Kasper Sandberg <lkml@xxxxxxxxxxx> wrote: > > > From: Kasper Sandberg <lkml@xxxxxxxxxxx> > > Subject: Re: Sharing disks amoung multiple software RAIDs > > To: "Justin Piszcz" <jpiszcz@xxxxxxxxxxxxxxx> > > Cc: "Alex Davis" <alex14641@xxxxxxxxx>, linux-raid@xxxxxxxxxxxxxxx, > linux-kernel@xxxxxxxxxxxxxxx > > Date: Thursday, May 1, 2008, 9:39 PM > > On Thu, 2008-05-01 at 08:50 -0400, Justin Piszcz wrote: > > > > > > On Thu, 1 May 2008, Alex Davis wrote: > > > > > > > Is this a bad thing? I'm guessing that it is, > > but I want independent > > > > confirmation before I spoke to someone I know > > who's doing this. > > > > > > > > Thanks > > > > > > > > > > > > > > > ________________________________________________________________________ > ____________ > > > > Be a better friend, newshound, and > > > > know-it-all with Yahoo! Mobile. Try it now. > > http://mobile.yahoo.com/;_ylt=Ahu06i62sR8HDtDypao8Wcj9tAcJ > > > > -- > > > > To unsubscribe from this list: send the line > > "unsubscribe linux-raid" in > > > > the body of a message to > > majordomo@xxxxxxxxxxxxxxx > > > > More majordomo info at > > http://vger.kernel.org/majordomo-info.html > > > > > > > > > > What is the use case, why would you want to do that? > > > I have seen people on the list do it before, for > > example are you going to > > > be utilizing both raids at the same time? If so, I > > would advise against > > > it. > > > > > > What is the reasoning? > > > > I do this! > > > > is this really bad? i would surely like a list of reasons > > why.. > > > > I do it because.. well.. first off, it allows me to have > > /boot on > > different raidlevel than / or /home without extra disks. > > secondly, it allows me to with the same disks use different > > filesystems.. for instance, it allows me to have /home > > encrypted with > > dm-crypt, while still raided.. Not that i would mind > > encrypting / > > and /home as 1 partition, but it creates a whole slew of > > issues with > > having to create initrd and stuff.. > > > > I realize that performance probably suffers abit from this, > > but well.. > > is there any stability or security wise risk? i mostly use > > raid1 and > > raid5 only.. > > > I would guess if the RAIDs are heavily used simultaneously it could > cause the disk head actuators to jump around more, causing more wear > and tear. > > > > ________________________________________________________________________ > ____________ > Be a better friend, newshound, and > know-it-all with Yahoo! Mobile. Try it now. > http://mobile.yahoo.com/;_ylt=Ahu06i62sR8HDtDypao8Wcj9tAcJ > -- > To unsubscribe from this list: send the line "unsubscribe linux-raid" in > the body of a message to majordomo@xxxxxxxxxxxxxxx > More majordomo info at http://vger.kernel.org/majordomo-info.html > > -- To unsubscribe from this list: send the line "unsubscribe linux-raid" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
