Re: GEOM, Vinum difference
On Wed, 2007-08-22 at 08:51 +0400, Rakhesh Sasidharan wrote: Lowell Gilbert wrote: Rakhesh Sasidharan [EMAIL PROTECTED] writes: I see that if I want to do disk striping/ concating/ mirroring, FreeBSD offers the GEOM utilities and the Vinum LVM (which fits into the GEOM architecture). Why do we have two different ways of doing the ... definitely a difference. Thanks! Another (related) question: both gvinum and the geom utilities like gmirror and gstripe etc provide for RAID0, RAID1, and RAID3. Any advantages/ disadvantages of using one instead of the other? It depends greatly upon your application and needs. A common practice in a common 6-disk capable server is to use a RAID1 set of smaller capacity, faster speed/RPM disks for RAID1 for the system file systems, while using a combination of larger, slower disks in a RAID1 set, then RAID0'd together for both space, performance, and redundancy. RAID1+0. ~BAS ___ freebsd-questions@freebsd.org mailing list http://lists.freebsd.org/mailman/listinfo/freebsd-questions To unsubscribe, send any mail to [EMAIL PROTECTED]
Re: GEOM, Vinum difference
Rakhesh Sasidharan wrote: Another (related) question: both gvinum and the geom utilities like gmirror and gstripe etc provide for RAID0, RAID1, and RAID3. Any advantages/ disadvantages of using one instead of the other? There has been a polemic between Greg Lehey and PJ Dawidek about the comparative advantages of raid3 and raid5. You can find the exchanges on Google. One example being: http://arkiv.freebsd.se/?ml=freebsd-performancea=2004-08t=227183 As far as i remember there are arguments showing that raid3 is better than raid5 both in terms of speed and of data security. It seems that raid5 has mostly a hype factor for him, but i may err. Anyways it is for such reasons that in the modern geom system, raid3 has been implemented and not raid5. But vinum has been ported to the geom framework for the benefit of old users, or of people who like it. For example if you are using FreeBSD-4 or DragonFlyBSD, vinum is the standard tool, and you may prefer getting expertise in just one tool. Finally none of these raid systems is really good, both for performance and security. If you are concerned with your data and want good write speed, you must buy enough disks and use raid 10. Another important factor is ease of use. The geom tools, gmirror, gstripe, graid3, etc. are *very* easy to use. The documentation in the man pages is clear, sufficient for doing work, and not too long. On the contrary, vinum was traditionaly documented in a very hermetic way. But more recently, Greg Lehey has provided a very clear chapter of his book on his web site which can be recommanded, but is not short. Note the documentation is a critical aspect of such systems because its lack may bite you in case a disk crashes and you need to adopt correct procedures under stress. Also for some time the gvinum stuff was extremely buggy, and was completely non functional when i tried it. I hope it is fixed now. -- Michel TALON ___ freebsd-questions@freebsd.org mailing list http://lists.freebsd.org/mailman/listinfo/freebsd-questions To unsubscribe, send any mail to [EMAIL PROTECTED]
Re: GEOM, Vinum difference
Michel Talon wrote: Rakhesh Sasidharan wrote: Another (related) question: both gvinum and the geom utilities like gmirror and gstripe etc provide for RAID0, RAID1, and RAID3. Any advantages/ disadvantages of using one instead of the other? There has been a polemic between Greg Lehey and PJ Dawidek about the comparative advantages of raid3 and raid5. You can find the exchanges on Google. One example being: http://arkiv.freebsd.se/?ml=freebsd-performancea=2004-08t=227183 As far as i remember there are arguments showing that raid3 is better than raid5 both in terms of speed and of data security. It seems that raid5 has mostly a hype factor for him, but i may err. Anyways it is for such reasons that in the modern geom system, raid3 has been implemented and not raid5. But vinum has been ported to the geom framework for the benefit of old users, or of people who like it. For example if you are using FreeBSD-4 or DragonFlyBSD, vinum is the standard tool, and you may prefer getting expertise in just one tool. Finally none of these raid systems is really good, both for performance and security. If you are concerned with your data and want good write speed, you must buy enough disks and use raid 10. Another important factor is ease of use. The geom tools, gmirror, gstripe, graid3, etc. are *very* easy to use. The documentation in the man pages is clear, sufficient for doing work, and not too long. On the contrary, vinum was traditionaly documented in a very hermetic way. But more recently, Greg Lehey has provided a very clear chapter of his book on his web site which can be recommanded, but is not short. Note the documentation is a critical aspect of such systems because its lack may bite you in case a disk crashes and you need to adopt correct procedures under stress. Also for some time the gvinum stuff was extremely buggy, and was completely non functional when i tried it. I hope it is fixed now. Great, thanks Michael! :) That's just the sort of info I was looking for ... Regards, - Rakhesh http://rakhesh.com/ ___ freebsd-questions@freebsd.org mailing list http://lists.freebsd.org/mailman/listinfo/freebsd-questions To unsubscribe, send any mail to [EMAIL PROTECTED]
Re: GEOM, Vinum difference
Rakhesh Sasidharan [EMAIL PROTECTED] writes: I see that if I want to do disk striping/ concating/ mirroring, FreeBSD offers the GEOM utilities and the Vinum LVM (which fits into the GEOM architecture). Why do we have two different ways of doing the same tasks -- any advantages/ disadvantages to either approach? I did check the archives before posting this question. Got a couple of hits, but they seem to be old info. Hence this question. The GEOM utilities seem to be newer, fancier, and probably the future. Vinum seems to be how things used to happen earlier. After GEOM was introduced, if Vinum had been discarded, I would have understood. But it wasn't. Instead, it was rewritten for GEOM and is probably still actively maintained. So I wonder why we have two ways of doing the same tasks ... What I understand from the archives is that Vinum was _probably_ rewritten for GEOM coz the GEOM utilities were still new and not as time tested as Vinum. Is that the case? So will Vinum continue to be around for a while or it be discarded? geom(4) does not provide RAID. It provides framework services that are used by gvinum(8), (and by many other disk-related capabilities). ___ freebsd-questions@freebsd.org mailing list http://lists.freebsd.org/mailman/listinfo/freebsd-questions To unsubscribe, send any mail to [EMAIL PROTECTED]
Re: GEOM, Vinum difference
Lowell Gilbert wrote: Rakhesh Sasidharan [EMAIL PROTECTED] writes: I see that if I want to do disk striping/ concating/ mirroring, FreeBSD offers the GEOM utilities and the Vinum LVM (which fits into the GEOM architecture). Why do we have two different ways of doing the same tasks -- any advantages/ disadvantages to either approach? I did check the archives before posting this question. Got a couple of hits, but they seem to be old info. Hence this question. The GEOM utilities seem to be newer, fancier, and probably the future. Vinum seems to be how things used to happen earlier. After GEOM was introduced, if Vinum had been discarded, I would have understood. But it wasn't. Instead, it was rewritten for GEOM and is probably still actively maintained. So I wonder why we have two ways of doing the same tasks ... What I understand from the archives is that Vinum was _probably_ rewritten for GEOM coz the GEOM utilities were still new and not as time tested as Vinum. Is that the case? So will Vinum continue to be around for a while or it be discarded? geom(4) does not provide RAID. It provides framework services that are used by gvinum(8), (and by many other disk-related capabilities). Missed that one! :) There's no geom utility for RAID5, so that's definitely a difference. Thanks! Another (related) question: both gvinum and the geom utilities like gmirror and gstripe etc provide for RAID0, RAID1, and RAID3. Any advantages/ disadvantages of using one instead of the other? Thanks, - Rakhesh http://rakhesh.com/ ___ freebsd-questions@freebsd.org mailing list http://lists.freebsd.org/mailman/listinfo/freebsd-questions To unsubscribe, send any mail to [EMAIL PROTECTED]
GEOM, Vinum difference
Hi, I see that if I want to do disk striping/ concating/ mirroring, FreeBSD offers the GEOM utilities and the Vinum LVM (which fits into the GEOM architecture). Why do we have two different ways of doing the same tasks -- any advantages/ disadvantages to either approach? I did check the archives before posting this question. Got a couple of hits, but they seem to be old info. Hence this question. The GEOM utilities seem to be newer, fancier, and probably the future. Vinum seems to be how things used to happen earlier. After GEOM was introduced, if Vinum had been discarded, I would have understood. But it wasn't. Instead, it was rewritten for GEOM and is probably still actively maintained. So I wonder why we have two ways of doing the same tasks ... What I understand from the archives is that Vinum was _probably_ rewritten for GEOM coz the GEOM utilities were still new and not as time tested as Vinum. Is that the case? So will Vinum continue to be around for a while or it be discarded? - Rakhesh http://rakhesh.com/ ___ freebsd-questions@freebsd.org mailing list http://lists.freebsd.org/mailman/listinfo/freebsd-questions To unsubscribe, send any mail to [EMAIL PROTECTED]
