Re: [nlug] RAID question...
How exactly could this happen in the real world? I imagine that the most recently attached drive would be considered the master by the RAID controller and would be used to rebuild the other drive, but I'm just guessing since that seems to be the logical thing to do. Chris On Thu, Feb 18, 2010 at 12:16 PM, Richard Thomas r...@dicksonlife.comwrote: I couldn't find an answer to this, possibly because it would be a retarded thing to do but I was just wondering... Say you had mirrored (say hardware) RAID with two drives. Reboot the system with one drive unplugged, make some changes then reboot with the other unplugged (and the unplugged one plugged back in), make some different changes then reboot with both drives plugged back in, what is the expected outcome (or is it controller dependent). Rich -- You received this message because you are subscribed to the Google Groups NLUG group. To post to this group, send email to nlug-talk@googlegroups.com To unsubscribe from this group, send email to nlug-talk+unsubscr...@googlegroups.comnlug-talk%2bunsubscr...@googlegroups.com For more options, visit this group at http://groups.google.com/group/nlug-talk?hl=en -- You received this message because you are subscribed to the Google Groups NLUG group. To post to this group, send email to nlug-talk@googlegroups.com To unsubscribe from this group, send email to nlug-talk+unsubscr...@googlegroups.com For more options, visit this group at http://groups.google.com/group/nlug-talk?hl=en
Re: [nlug] RAID question...
If he got confused on which drive was which I could see the first half happening. I cannot fathom a reason switch, make shanges and reboot with both plugged in.. unless to see what would happen. In any case, your logic seems correct. Maybe Rich will try it and let us know. W On Thu, Feb 18, 2010 at 1:23 PM, Chris McQuistion cmcquist...@watkins.eduwrote: How exactly could this happen in the real world? I imagine that the most recently attached drive would be considered the master by the RAID controller and would be used to rebuild the other drive, but I'm just guessing since that seems to be the logical thing to do. Chris On Thu, Feb 18, 2010 at 12:16 PM, Richard Thomas r...@dicksonlife.comwrote: I couldn't find an answer to this, possibly because it would be a retarded thing to do but I was just wondering... Say you had mirrored (say hardware) RAID with two drives. Reboot the system with one drive unplugged, make some changes then reboot with the other unplugged (and the unplugged one plugged back in), make some different changes then reboot with both drives plugged back in, what is the expected outcome (or is it controller dependent). Rich -- You received this message because you are subscribed to the Google Groups NLUG group. To post to this group, send email to nlug-talk@googlegroups.com To unsubscribe from this group, send email to nlug-talk+unsubscr...@googlegroups.comnlug-talk%2bunsubscr...@googlegroups.com For more options, visit this group at http://groups.google.com/group/nlug-talk?hl=en -- You received this message because you are subscribed to the Google Groups NLUG group. To post to this group, send email to nlug-talk@googlegroups.com To unsubscribe from this group, send email to nlug-talk+unsubscr...@googlegroups.comnlug-talk%2bunsubscr...@googlegroups.com For more options, visit this group at http://groups.google.com/group/nlug-talk?hl=en -- You received this message because you are subscribed to the Google Groups NLUG group. To post to this group, send email to nlug-talk@googlegroups.com To unsubscribe from this group, send email to nlug-talk+unsubscr...@googlegroups.com For more options, visit this group at http://groups.google.com/group/nlug-talk?hl=en
Re: [nlug] RAID question...
- Richard Thomas r...@dicksonlife.com wrote: I couldn't find an answer to this, possibly because it would be a retarded thing to do but I was just wondering... Say you had mirrored (say hardware) RAID with two drives. Reboot the system with one drive unplugged, make some changes then reboot with the other unplugged (and the unplugged one plugged back in), make some different changes then reboot with both drives plugged back in, what is the expected outcome (or is it controller dependent). In clustered filesystems, this is referred to as split brain. It is why most clustered filesystems want you to have 3 machines minimum. For clustered systems, consider 3 machines and each can talk to the other 2. If one drops off line, the 2 still able to talk can be authoritative. The one that can not talk to any of the others knows it is the one that is isolated and shouldn't respond to filesystem requests. When it can reconnect it can then get updated and reconnect. If you have 2 machines, you can not determine if the other machine is dead or the network is down locally or remotely. The problem you introduce that isn't covered in most failover problems is the idea of rebooting to make the changes. If you hotswap out a drive the machine knows the drive was removed and when it returns it knows to rebuild. You don't have a condition of 2 drives in current condition and needing the other to be rebuilt. Most likely the solution would be to pick on to be rebuilt from and do it at the bios level. Otherwise boot from the drive you wish to be correct and then introduce the redundant drive after the controller has established a authoritative drive for the mirror to rebuild against. -- Steven Critchfield cri...@basesys.com -- You received this message because you are subscribed to the Google Groups NLUG group. To post to this group, send email to nlug-talk@googlegroups.com To unsubscribe from this group, send email to nlug-talk+unsubscr...@googlegroups.com For more options, visit this group at http://groups.google.com/group/nlug-talk?hl=en
Re: [nlug] KDE 4 vs KDE 3.5
On Thu, Feb 18, 2010 at 3:13 PM, Don Delp nesma...@gmail.com wrote: I have to admit to being a procrastinator, but I feel that I won't be able to hold off on switching to KDE 4 for much longer. I've been running Kubuntu 8.04 happily with KDE 3.5, but some applications (eg. Amarok) are only being updated for KDE4. When I first tried 4, I was not impressed. Has anyone else made the switch that can tell me that the water's fine? I tried 4.0, 4.1 and then 4.2, when each came out. Every version was really messed up for me. When I complained I was told to try Suse (rather than Ubuntu) if I wanted a good KDE install. Suse is rpm-based, so I never did. I've stuck to KDE, even though I put GNOME on my wife's computer, because I like the way it works. I can get by in GNOME, but it feels dumbed down to me. Things don't seem to have enough right-click options. Often, keys that I would expect to do something just don't respond in certain situations. I don't have it in front of me atm, but I remember having a hard time deleting dead entries from my wife's Program menu. The way it switched from being right-click driven to having buttons on the interface and back again to perform tasks seemed to be very arbitrary. I'm also not against other window managers. I've heard nice things about xfce, but the way it's configured on MythBuntu doesn't thrill me. I got used to Gnome over time. I had the same issues you describe.. seemed too simplistic. But now a few years later I really value the simplicity. As I get older I'm starting to care less about fancy right-click menus and more about getting things done so I can move on to whatever is next. Gnome seems right for me, right now. -- Greg Donald destiney.com | gregdonald.com -- You received this message because you are subscribed to the Google Groups NLUG group. To post to this group, send email to nlug-talk@googlegroups.com To unsubscribe from this group, send email to nlug-talk+unsubscr...@googlegroups.com For more options, visit this group at http://groups.google.com/group/nlug-talk?hl=en
Re: [nlug] RAID question...
Steven S. Critchfield wrote: - Richard Thomas r...@dicksonlife.com wrote: I couldn't find an answer to this, possibly because it would be a retarded thing to do but I was just wondering... Say you had mirrored (say hardware) RAID with two drives. Reboot the system with one drive unplugged, make some changes then reboot with the other unplugged (and the unplugged one plugged back in), make some different changes then reboot with both drives plugged back in, what is the expected outcome (or is it controller dependent). In clustered filesystems, this is referred to as split brain. It is why most clustered filesystems want you to have 3 machines minimum. For clustered systems, consider 3 machines and each can talk to the other 2. If one drops off line, the 2 still able to talk can be authoritative. The one that can not talk to any of the others knows it is the one that is isolated and shouldn't respond to filesystem requests. When it can reconnect it can then get updated and reconnect. If you have 2 machines, you can not determine if the other machine is dead or the network is down locally or remotely. The problem you introduce that isn't covered in most failover problems is the idea of rebooting to make the changes. If you hotswap out a drive the machine knows the drive was removed and when it returns it knows to rebuild. You don't have a condition of 2 drives in current condition and needing the other to be rebuilt. Most likely the solution would be to pick on to be rebuilt from and do it at the bios level. Otherwise boot from the drive you wish to be correct and then introduce the redundant drive after the controller has established a authoritative drive for the mirror to rebuild against. Yeah, hot swap avoids the ambiguity. I guess if the controller maintains any information internally, it would probably sync the newest drive to the oldest. Though it also might synchronize the second drive to the first. Though more likely it should throw an error and require the user to pick. Note that the scenario presented, both drives were already members of the array so, I guess, theoretically, neither should be regarded as more authoritative than the other. What made me think of this was I was pondering usage of mirrors as a rollback device. Pop one drive, do potentially dangerous changes, if they go wrong, just boot off the popped drive and rebuild to the one with the bad config. Again, hotswap should solve the issue. Though thinking about it, removing the one drive should remove it from the array, thus the drive which is added back to the array second should be the one overwritten (Though, possibly, any drive added to the array, even the first one, should be considered blank but it is an option to clear or not on my controller). I may try an experiment if I can dig out two old drives. -- You received this message because you are subscribed to the Google Groups NLUG group. To post to this group, send email to nlug-talk@googlegroups.com To unsubscribe from this group, send email to nlug-talk+unsubscr...@googlegroups.com For more options, visit this group at http://groups.google.com/group/nlug-talk?hl=en
Re: [nlug] KDE 4 vs KDE 3.5
Howard wrote: Amen, Greg. Was a long time Mandrake / Mandriva user with KDE. Also had FVWM2 on a multi-monitor system for a long time. Switched to Ubuntu a few years ago and became comfortable with that Gnome. But now I am trying to renew / revive my five monitor system(s) and these desktop managers are getting in the way. Compiz and NetworkManager are both a pox upon us all. I understand that they keep trying to gentrify linux to appeal to the muggles. Meanwhile, I keep hearing the siren song of Slackware, Arch and others. Hadn't thought about FVWM2 in quite a while. h. Howard I can't help feeling most of the window managers are chasing the wrong paradigm. Microsoft applies kludges to fix their problems and half the windows managers chase after them. I think it's time we divorced the tools from the document window. That doesn't mean putting them in their own window, that means have dedicated screen area for them that's sticky. Forget virtual desktops too, have a big single desktop area with go to bookmarks. Let's find a way away from the application-centric interface too. -- You received this message because you are subscribed to the Google Groups NLUG group. To post to this group, send email to nlug-talk@googlegroups.com To unsubscribe from this group, send email to nlug-talk+unsubscr...@googlegroups.com For more options, visit this group at http://groups.google.com/group/nlug-talk?hl=en
