Note: "permalinks" may not be as permanent as we would like,
direct links of old sources may well be a few messages off.
Hello Peter ! Thank you for your precious answer ! I will see what I could get from HP on this point. Again, many thanks. Petrakis, Peter a écrit : > Hello Hervé, > > The cciss driver doesn't support i/o barriers, however, if you have a BBWC > (battery backed write cache) you should be fine. I recently explored the > possibility of adding barriers though the available specs don't confirm > whether SYNCHRONIZE CACHE is supported, they do however support the ability > to flush the entire cache, which would kill performance. I've been in contact with HP in search of a definitive answer and what I got was "there's a new spec coming out" and they don't know when it'll be ready. > > I agree that there ought to be a way to flush the cache to the physical disks associated with a single logical volume but until there's a definitive answer, any i/o barrier implementation would essentially be unpredictable. > Feel free to ask HP regarding this issue :) > > Peter > > P.S. http://cciss.sourceforge.net > > > >> -----Original Message----- >> From: drbd-user-bounces at linbit.com [mailto:drbd-user-bounces at linbit.com] >> On Behalf Of GAUTIER Hervé >> Sent: Monday, November 03, 2008 8:12 AM >> To: drbd-user at linbit.com >> Subject: [DRBD-user] I/O barrier problem >> >> >> Hi there ! >> >> I need some more explanations in order to know from where comes a >> barrier problem (message local disk flush failed with status -95). >> >> I have identified the following different levels of the chain that may >> be involved: >> - OS: I am currently running on Red Hat Enterprise Linux ES release 4 >> (Nahant Update 6) kernel 2.6.9-67.ELsmp. Is there a minimum required >> kernel version for the barriers implementation ? >> - DRBD: The current version I am using is drbd-8.2.5. >> - Drivers: I currently use disks connected on a HP Smart Array 642 >> Controller using the cciss driver 2.6.16 provided by the Red Hat >> Enterprise Linux ES release 4 (Nahant Update 6). I haven't seen any >> option on this driver. >> - Controller: I will check in there is any cache option in the HP Smart >> Array 642 Controller firmware. >> - Disks: I will try to find any information on the disks used in order >> to check if the used some cache. >> >> Anything else I have forgotten ? >> >> Thank in advance, >> >> Best regards. >> >> -- >> Hervé GAUTIER >> >> _______________________________________________ >> drbd-user mailing list >> drbd-user at lists.linbit.com >> http://lists.linbit.com/mailman/listinfo/drbd-user >> > _______________________________________________ > drbd-user mailing list > drbd-user at lists.linbit.com > http://lists.linbit.com/mailman/listinfo/drbd-user > > -- Hervé GAUTIER