From mboxrd@z Thu Jan 1 00:00:00 1970 From: Phil Turmel Subject: Re: RAID newbie, 1 vs 5, chunk sizes Date: Mon, 16 Jun 2014 16:13:08 -0400 Message-ID: <539F4FD4.9070504@turmel.org> References: <539E5504.1080809@turmel.org> <539EFF1C.3000009@turmel.org> Mime-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: QUOTED-PRINTABLE Return-path: In-Reply-To: Sender: linux-raid-owner@vger.kernel.org To: =?UTF-8?B?TnVubyBNYWdhbGjDo2Vz?= , linux-raid@vger.kernel.org List-Id: linux-raid.ids On 06/16/2014 12:14 PM, Nuno Magalh=C3=A3es wrote: > Thanks for the tips. > Back to a previous question (assuming i have the drives sorted out fi= rst): >=20 > If i create a RAID10 with 3 1TB drives, with --layout=3Df2, would thi= s > give me 2TB of space +1TB redundancy? Is this a 1E? > Using: mdadm --create /dev/md0 --verbose --chunk=3D128 --level=3D10 > --layout=3Df2 --raid-devices=3D3 /dev/sd[abd]1 No, you'll have 1.5T of available space mirrored by halves. > If so, what would be the difference to a RAID5: > mdadm --create /dev/md0 --verbose --chunk=3D512 --level=3D5 > --raid-devices=3D3 /dev/sd[abd]1 >=20 > Besides one having redundancy and the other having parity; and that > RAID5 must compute parity (is that really so horrendously slow > nowadays?). You can't fit the redundancy for 2T of data into 1T without some form o= f parity raid. > Other than tiobench, any other benchmarking tools you guys recommend? > (I've decided to just go slow and test every layer out before moving > to the next, i.e. 1st RAID, LVM, FSs, Xen, apps.) I'll leave that one for others. . . Just don't expect dd to be very us= eful. Phil -- 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