From mboxrd@z Thu Jan 1 00:00:00 1970 From: Keld =?iso-8859-1?Q?J=F8rn?= Simonsen Subject: Re: Grow a RAID-10 Date: Thu, 3 Jul 2008 10:46:53 +0200 Message-ID: <20080703084653.GA29152@rap.rap.dk> References: <486BF974.70508@amfes.com> <20080702231026.GA15028@rap.rap.dk> <486C2FB3.3050403@amfes.com> Mime-Version: 1.0 Content-Type: text/plain; charset=iso-8859-1 Content-Transfer-Encoding: QUOTED-PRINTABLE Return-path: Content-Disposition: inline In-Reply-To: <486C2FB3.3050403@amfes.com> Sender: linux-raid-owner@vger.kernel.org To: "Daniel L. Miller" Cc: linux-raid@vger.kernel.org List-Id: linux-raid.ids On Wed, Jul 02, 2008 at 06:47:31PM -0700, Daniel L. Miller wrote: > Keld J=F8rn Simonsen wrote: > >On Wed, Jul 02, 2008 at 02:56:04PM -0700, Daniel L. Miller wrote: > > =20 > >>I currently have a RAID10 across (4) SATA drives. It looks like I'= m=20 > >>going to need to grow in the near future. Any tips for a procedure= for=20 > >>this? My current plan: > >> > >>1. Add a PCI SATA controller (MB had 4 SATA + 4 RAID SATA, it's a = Tyan=20 > >>MB with a NFORCE chipset, I'm not sure if I want/can use the RAID S= ATA=20 > >>ports as plain SATA connections). > >> =20 > > > >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? > > > > =20 > My mistake. Confused this one with another system. Only have 4 port= s=20 > available. I did have the option of using the Nvidia RAID - which I = did=20 > 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 matter= s,=20 > it's a Tyan S2892, a "Thunder K8SE". nForce Pro2200 and AMD8131 PCI-= X=20 > chipsets. So it has both PCI-X bus and PCI-E bus. You want to attact 2 more drive= s=20 and you need a sata controller. This could probably both be attached vi= a 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 c= an > >deliver.=20 > > > > =20 > >>2. Add 2 more drives - not necessarily the same size as the existi= ng=20 > >>(they were all 4 the same) > >> > >>3. Execute "mdadm --grow /dev/md0" > >> =20 > > > >What kind of raid10 do you have?>=20 > > =20 > I don't understand this question either. >=20 > 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 >=20 > Update Time : Wed Jul 2 18:46:15 2008 > State : clean > Active Devices : 4 > Working Devices : 4 > Failed Devices : 0 > Spare Devices : 0 >=20 > Layout : near=3D2, far=3D1 > Chunk Size : 32K >=20 > UUID : 9d94b17b:f5fac31a:577c252b:0d4c4b2a > Events : 0.10941692 >=20 > 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=3D2). You may benefit from a raid10,f2 layout, as this ha= s faster=20 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 no= t so important, as raid10,n2 cannot deliver that high performance.=20 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" i= n the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html