Regarding the writeback cache on disks, what is the recommended method to disable the cache? Through HBA firmware, or via Solaris?
On Sun, Mar 11, 2012 at 7:00 AM, <zfs-discuss-requ...@opensolaris.org>wrote: > > Message: 1 > Date: Sat, 10 Mar 2012 09:09:52 -0500 > From: John D Groenveld <jdg...@elvis.arl.psu.edu> > To: zfs-discuss@opensolaris.org > Subject: Re: [zfs-discuss] Any recommendations on Perc H700 controller > on Dell Rx10 ? > Message-ID: <201203101409.q2ae9qw0021...@elvis.arl.psu.edu> > Content-Type: text/plain; charset=us-ascii > > In message < > caniy96a2t1n2m0kpmdx2rbodogjofetoth2qe4rot6x-xn8...@mail.gmail.com> > , Sriram Narayanan writes: > >At work, I have an R510, and R610 and an R710 - all with the H700 PERC > >controller. > > BTW with some effort, Dell's sales critter will sell you the > H200 LSI SAS HBA as a replacement for the H700 LSI MegaRAID > controller for those boxes. > > >Based on experiments, it seems like there is no way to bypass the PERC > >controller - it seems like one can only access the individual disks if > >they are set up in RAID0 each. > > Did you try deleting all of the RAID0 Virtual Disks and > then enabling JBOD? > # MegaCli -AdpSetProp -EnableJBOD -1 -aALL > # MegaCli -PDMakeJBOD -PhysDrv[E0:S0,E1:S1,...] -aALL > > John > groenv...@acm.org > > > > ------------------------------ > > Message: 2 > Date: Sat, 10 Mar 2012 09:10:06 -0500 > From: Edward Ned Harvey > <opensolarisisdeadlongliveopensola...@nedharvey.com> > To: "'Sriram Narayanan'" <sri...@belenix.org>, > <zfs-discuss@opensolaris.org> > Subject: Re: [zfs-discuss] Any recommendations on Perc H700 controller > on Dell Rx10 ? > Message-ID: <000001ccfec7$8250c460$86f24d20$@nedharvey.com> > Content-Type: text/plain; charset="us-ascii" > > > From: zfs-discuss-boun...@opensolaris.org [mailto:zfs-discuss- > > boun...@opensolaris.org] On Behalf Of Sriram Narayanan > > > > Based on experiments, it seems like there is no way to bypass the PERC > > controller - it seems like one can only access the individual disks if > > they are set up in RAID0 each. > > The first consideration to remember is: When your disks are set up by one > of these controllers, you won't be able to move these disks to a generic > controller-less system and expect them to work. You are dependent on the > raid hardware (or compatible competitors) to make the disks accessible. > Just keep this in mind whenever your system warranty renewal period is > approaching. Also, if you need to move these disks to a new system that > has > a compatible controller, you must configure them exactly the same as they > are on this system - but don't initialize. > > The second consideration you should think about is the writeback cache. If > you have any SSD dedicated log device, you actually get the best > performance > by DISABLING the writeback on all disks. The second best configuration is > without SSD, you enable writeback on all disks. And obviously the worst > configuration, you have no SSD and no writeback. > > > > ------------------------------ > > _______________________________________________ > zfs-discuss mailing list > http://mail.opensolaris.org/mailman/listinfo/zfs-discuss >
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