From mboxrd@z Thu Jan 1 00:00:00 1970 From: "Daniel L. Miller" Subject: Re: Grow a RAID-10 Date: Thu, 03 Jul 2008 09:29:29 -0700 Message-ID: <486CFE69.8030501@amfes.com> References: <486BF974.70508@amfes.com> <20080702231026.GA15028@rap.rap.dk> <486C2FB3.3050403@amfes.com> <20080703084653.GA29152@rap.rap.dk> Mime-Version: 1.0 Content-Type: text/plain; charset=ISO-8859-1; format=flowed Content-Transfer-Encoding: QUOTED-PRINTABLE Return-path: In-Reply-To: <20080703084653.GA29152@rap.rap.dk> Sender: linux-raid-owner@vger.kernel.org To: linux-raid@vger.kernel.org List-Id: linux-raid.ids Keld J=F8rn Simonsen wrote: > On Wed, Jul 02, 2008 at 06:47:31PM -0700, Daniel L. Miller wrote: > =20 >> Keld J=F8rn Simonsen wrote: >> =20 >>> On Wed, Jul 02, 2008 at 02:56:04PM -0700, Daniel L. Miller wrote: >>> =20 >>> =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 procedur= e 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 = SATA=20 >>>> ports as plain SATA connections). >>>> =20 >>>> =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 >>> =20 >> My mistake. Confused this one with another system. Only have 4 por= ts=20 >> available. I did have the option of using the Nvidia RAID - which I= did=20 >> NOT enable. >> =20 > > 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 hav= e > all been using to run SW raid, and I have not experienced any problem= s > 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. > > =20 >> What "kind" of pci bus? Don't understand the question. If it matte= rs,=20 >> it's a Tyan S2892, a "Thunder K8SE". nForce Pro2200 and AMD8131 PCI= -X=20 >> chipsets. >> =20 > > So it has both PCI-X bus and PCI-E bus. You want to attact 2 more dri= ves=20 > 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. > > =20 >>> 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.=20 >>> >>> =20 >>> =20 >>>> 2. Add 2 more drives - not necessarily the same size as the exist= ing=20 >>>> (they were all 4 the same) >>>> >>>> 3. Execute "mdadm --grow /dev/md0" >>>> =20 >>>> =20 >>> What kind of raid10 do you have?>=20 >>> =20 >>> =20 >> 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=3D2, far=3D1 >> 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 >> =20 > > 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 = has 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 = not > 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 > =20 This is our all-in-one server. The raid is the primary storage for=20 everything - day-to-day operations files, quickbooks data, virtual=20 machines. O/S and programs are on a separate non-raid drive. -- Daniel -- 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