op 30-08-14 11:53, Roger Heflin schreef: > That means you need an external config tool (serial, ilo or IMM that > allows remote console access), I rarely go into the data center that > all of the hw I run is in, and because of the remote console access > can fix all but truly broken hw without having hands in the DC). That's a way to repear something what's broken. Not a more redundant solution I was looking for. But you are right, it helps a lot. I use IPMI for remote console. And on some machines a serial console. What I don't like about IPMI is that the part on the server is -so far I know- not really open source and I cannot update it for security, so I can only use it from a secure subnet initiated by another machine. A serial connection can be done OSS, but you need another machine in the direct neighborhood, and it's not really nice. So in both cases you need 2 machines with at least to IP's. Many firms here have DSL with only one IP. > For most low end enterprise hw this option adds $200-300 to the price. It's standard on the machines I buy (Supermicro). > If using the simplest (serial) the given mb bios must support > serial and all add-on bioses must also properly support serial. I > have messed with machines that when using serial you cannot see/access > some of the add on bioses which limits what you can do. ILO/IMM > (full graphics console remote type setups) don't have this deficiency > and can in some cases actually allow one to present a remote boot cd > to a device and rescue boot it. Not sure this is possible with OSS applications. > The MBR did not get broken, it was broken like this as originally > designed 30 years ago, it was always setup to be only able to deal > with totally dead drivers (ie drive not showing up at all). I think you mean the bios. Some bios-es can do fakeraid, and I expect they can boot from another disk when the first disk is corrupt. But you cannot use mdadm then, what I would like. With regards, Paul van der Vlis. > On Sat, Aug 30, 2014 at 3:35 AM, Paul van der Vlis <paul@xxxxxxxxxxxxx> wrote: >> op 30-08-14 00:38, Roger Heflin schreef: >>> No bios I have seen automatically handles it unless the disks are >>> total dead, >> >> That's my experience too. >> >>> some of the hardware raid controlers may properly deal >>> with a disk returning an error and go to the other mirror, the low end >>> quality raid controllers start around $200. >> >> Hardware raid controllers have other disadvantages, like using a >> proprietary format for storing information on disk. And in many cases >> you have to use tools from the manufacturer. That are reasons for me to >> like mdadm. >> >> Maybe it could be done with a hardware raid controller in JBOD mode. >> >> ( And hardware controllers are not perfect too, I've seen simular >> problems with an HP smart array. First when I've removed the first >> harddisk the system did boot from the second. ) >> >>> Outside of the raid controllers I don't believe any of the bioses >>> themselves will do it, so you are unlikely to find any hardware that >>> does that. >> >> It could be done with a PCIe card too. Some kind of fake-raid adapter >> what uses mdadm. >> >>> Likely he is talking about putting the boot block on multiple disks >>> and and use the bbr menu or the bios boot disk selection to pick >>> another disk. >> >> Not sure what a "bbr menu" is. But realize that the servers I use are >> remote. >> >> With regards, >> Paul van der Vlis. >> >>> On Fri, Aug 29, 2014 at 4:47 PM, Paul van der Vlis <paul@xxxxxxxxxxxxx> wrote: >>>> Hi Roberto, >>>> >>>> op 29-08-14 22:44, Roberto Spadim schreef: >>>>> i use two or more boot disks, if the first raid1 disk don't boot bios >>>>> go to second boot disk, third, etc etc, >>>> >>>> In my opinion this only works when the boot-disk is completely defect or >>>> removed. Not when the data in the MBR on that boot-disk is corrupt. >>>> >>>> Or did you test this, or do you have other reasons to believe that your >>>> bios will handle this correct? >>>> >>>> With the boot-disk I mean the disk what's in the bios the first disk. So >>>> this could also be the second raid1 disk. Or an USB stick. >>>> >>>>> you must write grub to mbr of each disk >>>> >>>> Of course. >>>> >>>> With regards, >>>> Paul van der Vlis. >>>> >>>>> i'm using dell server r410 if i'm not wrong >>>>> >>>>> 2014-08-29 17:31 GMT-03:00 Paul van der Vlis <paul@xxxxxxxxxxxxx>: >>>>>> Hello, >>>>>> >>>>>> I like mdadm and I am using it many years. But in my opinion it has one >>>>>> disadvantage: when the MBR of the boot-disk is corrupt, the machine will >>>>>> not boot. >>>>>> >>>>>> A bios could check this. Wait for some kind of signal from Grub or >>>>>> Linux, and after a timeout boot from another disk. But I don't know >>>>>> about a bios with that feature. >>>>>> >>>>>> A PCIe card could do something like that, but I don't know about such a >>>>>> PCIe card. >>>>>> >>>>>> Is there such hardware? >>>>>> What do you do to avoid this problem? >>>>>> >>>>>> With regards, >>>>>> Paul van der Vlis. >>>>>> >>>>>> >>>>>> >>>>>> >>>>>> -- >>>>>> Paul van der Vlis Linux systeembeheer, Groningen >>>>>> http://www.vandervlis.nl/ >>>>>> >>>>>> -- >>>>>> 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 >>>>> >>>>> >>>>> >>>> >>>> >>>> >>>> >>>> >>>> -- >>>> Paul van der Vlis Linux systeembeheer, Groningen >>>> http://www.vandervlis.nl/ >>>> >>>> -- >>>> 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 >>> >> >> >> >> >> >> -- >> Paul van der Vlis Linux systeembeheer, Groningen >> http://www.vandervlis.nl/ >> >> -- >> 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 > -- Paul van der Vlis Linux systeembeheer, Groningen http://www.vandervlis.nl/ -- 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
