On Wed, Jul 02, 2008 at 06:47:31PM -0700, Daniel L. Miller wrote: > Keld Jørn Simonsen wrote: > >On Wed, Jul 02, 2008 at 02:56:04PM -0700, Daniel L. Miller wrote: > > > >>I currently have a RAID10 across (4) SATA drives. It looks like I'm > >>going to need to grow in the near future. Any tips for a procedure for > >>this? My current plan: > >> > >>1. Add a PCI SATA controller (MB had 4 SATA + 4 RAID SATA, it's a Tyan > >>MB with a NFORCE chipset, I'm not sure if I want/can use the RAID SATA > >>ports as plain SATA connections). > >> > > > >Why not use the mobo raid sata ports? They are probably faster than a > >controller on the pci bus. What kind of pci bus do you have? > > > > > My mistake. Confused this one with another system. Only have 4 ports > available. I did have the option of using the Nvidia RAID - which I did > NOT enable. Yes, it is fine not to use the two on-board raid controllers in raid mode, but just to use SW raid on them. I have a similar mobo with 2 sata controllers and the ability to attach 8 sata drives, which I have all been using to run SW raid, and I have not experienced any problems yet with this setup. I understand that your mobo has 4 onboard sata connections, and that these are already in use for the current array. > What "kind" of pci bus? Don't understand the question. If it matters, > it's a Tyan S2892, a "Thunder K8SE". nForce Pro2200 and AMD8131 PCI-X > chipsets. So it has both PCI-X bus and PCI-E bus. You want to attact 2 more drives and you need a sata controller. This could probably both be attached via the PCI-X bus and the PCI-E bus. It seems like the PCI-X bus - with a 133 MHz possibility counld be the faster of the 2, but given you will only have 2 more drives, both PCI-X and PCI-E are prossibilties. > >PCI-E 1x is likely to be too slow for a 4-drive raid10,f2 array. > >My 4-drive raid10,f2 delivers about 320 MB/s and newer disks should be > >able to deliver 360 MB/s - well above the 250 MB/s that a PCI-E 1x can > >deliver. > > > > > >>2. Add 2 more drives - not necessarily the same size as the existing > >>(they were all 4 the same) > >> > >>3. Execute "mdadm --grow /dev/md0" > >> > > > >What kind of raid10 do you have?> > > > I don't understand this question either. > > mdadm --detail /dev/md0 > /dev/md0: > Version : 00.90.03 > Creation Time : Tue Oct 3 19:11:53 2006 > Raid Level : raid10 > Array Size : 312581632 (298.10 GiB 320.08 GB) > Used Dev Size : 156290816 (149.05 GiB 160.04 GB) > Raid Devices : 4 > Total Devices : 4 > Preferred Minor : 0 > Persistence : Superblock is persistent > > Update Time : Wed Jul 2 18:46:15 2008 > State : clean > Active Devices : 4 > Working Devices : 4 > Failed Devices : 0 > Spare Devices : 0 > > Layout : near=2, far=1 > Chunk Size : 32K > > UUID : 9d94b17b:f5fac31a:577c252b:0d4c4b2a > Events : 0.10941692 > > Number Major Minor RaidDevice State > 0 8 0 0 active sync /dev/sda > 1 8 16 1 active sync /dev/sdb > 2 8 32 2 active sync /dev/sdc > 3 8 48 3 active sync /dev/sdd I was takling about the layout, and you have a n2 layout (standard raid10 - near=2). You may benefit from a raid10,f2 layout, as this has faster read capabilities, but I think it is not possible on the fly to rearrange a raid10,n2 array to a raid10,f2 array. Given that you have a raid10,n2 layout, the speeds of the busses are not so important, as raid10,n2 cannot deliver that high performance. I would expect less than 100 MB/s coming out of your 2 extra disks. What is the use for your raid? is it a database, a file server, a web server or the like? Best regards keld -- 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
