From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from lists.gentoo.org (pigeon.gentoo.org [208.92.234.80]) by finch.gentoo.org (Postfix) with ESMTP id 8185B138E66 for ; Mon, 24 Feb 2014 06:27:26 +0000 (UTC) Received: from pigeon.gentoo.org (localhost [127.0.0.1]) by pigeon.gentoo.org (Postfix) with SMTP id 869DBE0B8C; Mon, 24 Feb 2014 06:27:18 +0000 (UTC) Received: from mail-yh0-f52.google.com (mail-yh0-f52.google.com [209.85.213.52]) (using TLSv1 with cipher ECDHE-RSA-RC4-SHA (128/128 bits)) (No client certificate requested) by pigeon.gentoo.org (Postfix) with ESMTPS id 66108E0B7D for ; Mon, 24 Feb 2014 06:27:17 +0000 (UTC) Received: by mail-yh0-f52.google.com with SMTP id a41so4767680yho.39 for ; Sun, 23 Feb 2014 22:27:16 -0800 (PST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20120113; h=mime-version:date:message-id:subject:from:to:content-type; bh=WKyL2zgXx58/LVZ94P2yq+NK6sJUfAi/lPl7xIIqC8g=; b=nhw6g/ZmDt7acPlKaI9HiTTstQ3+Nt96XdsAJ8CLooYuc6AlVbiM4YPVlXYqbzePKV 0qfJX+krFuXumYhn9XT6mYf5SU8kCFCH4o+/8TWc9LAa8YkyHNcSbgCfD9/NXm9SZF65 tMP71Up1qHeJtd+EwG1+a2I/c4i+x+39oo+ND8u3EEg4JrpSAOti9pO7vc+D0iPv5/3f 9kGD4pLH++G4Oe7kRMByjpC2nReKn1p3cqwe1bM23g97GARDlmt6oyvScDVwrv/s13eh uxYoPJ+o6MRWIyMUush8b/ov0lDGLOMQrGzP+GAURQLBteEPx2uRYitGa2lUCHNe3E8P s8zw== Precedence: bulk List-Post: List-Help: List-Unsubscribe: List-Subscribe: List-Id: Gentoo Linux mail X-BeenThere: gentoo-user@lists.gentoo.org Reply-to: gentoo-user@lists.gentoo.org MIME-Version: 1.0 X-Received: by 10.236.180.33 with SMTP id i21mr28810991yhm.101.1393223236596; Sun, 23 Feb 2014 22:27:16 -0800 (PST) Received: by 10.170.40.71 with HTTP; Sun, 23 Feb 2014 22:27:16 -0800 (PST) Date: Mon, 24 Feb 2014 03:27:16 -0300 Message-ID: Subject: [gentoo-user] RAID 1 vs RAID 0 - Read perfonmance From: Facundo Curti To: gentoo-user@lists.gentoo.org Content-Type: multipart/alternative; boundary=20cf305e23991c380404f32110d7 X-Archives-Salt: ec14ae0d-1cf5-4284-8647-cb76f498c8b1 X-Archives-Hash: ab1e9a7c1d2e4879618ce73fd1d9aaea --20cf305e23991c380404f32110d7 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: quoted-printable Hi. I am again, with a similar question to previous. I want to install RAID on SSD's. Comparing THEORETICALLY, RAID0 (stripe) vs RAID1 (mirrior). The performance would be something like this: n=3D number of disks reads: raid1: n*2 raid0: n*2 writes: raid1: n raid0: n*2 But, in real life, the reads from raid 0 doesn't work at all, because if you use "chunk size" from 4k, and you need to read just 2kb (most binary files, txt files, etc..). the read speed should be just of n. On the other side, I read over the net, that kernel don't support multithread reads on raid1. So, the read speed will be just n. Always. =C2= =BFIt is true? Anyway, my question is. =C2=BFWho have the best read speed for the day to d= ay? I'm not asking about reads off large files. I'm just asking in the "normal" use. Opening firefox, X, regular files, etc.. I can't find the guide definitive. It allways are talking about theoretically performance, or about "real life" but without benchmarks or reliable data. Having a RAID0 with SSD, and following [2] on "SSD Stripe Optimization" should I have the same speed as an RAID1? My question is because i'm between. 4 disks raid1, or RAID10 (I want redundancy anyway..). And as "raid 10" =3D 1+ 0. I need to know raid0 performance to take a choice... I don't need write speed, just read. =C2=BFAnyone knows the true about this? =C2=BFSomebody tried this? Thanx a lot.!! Bytes! ;) [1]http://www.pcstats.com/articleview.cfm?articleid=3D890&page=3D5 [2] http://www.overclock.net/t/484367/guide-all-you-ever-wanted-to-know-about-r= aid --20cf305e23991c380404f32110d7 Content-Type: text/html; charset=UTF-8 Content-Transfer-Encoding: quoted-printable
Hi. I am again, with a similar question to previous.<= /div>

I want to install RAID on SSD's.
Comparing THEORETICALLY, RAID0 (stripe) vs RAID1 (mirrior). The= performance would be something like this:

n=3D number of disks

reads:
=C2=A0=C2=A0raid1: n*2
=C2=A0=C2=A0raid0: n*2
<= br>
writes:
=C2=A0=C2=A0raid1: n
=C2=A0=C2=A0= raid0: n*2

But, in real life, the reads from raid = 0 doesn't work at all, because if you use "chunk size" from 4= k, and you need to read just 2kb (most binary files, txt files, etc..). the= read speed should be just of n.

On the other side, I read over the net, that kernel don= 't support multithread reads on raid1. So, the read speed will be just = n. Always. =C2=BFIt is true?

Anyway, my question i= s. =C2=BFWho have the best read speed for the day to day? I'm not askin= g about reads off large files. I'm just asking in the "normal"= ; use. Opening firefox, X, regular files, etc..

I can't find the guide definitive. It allways are t= alking about theoretically performance, or about "real life" but = without benchmarks or=C2=A0reliable data.

Havi= ng a RAID0 with SSD, and following [2] on "SSD Stripe Optimization&quo= t; should I have the same speed as an RAID1?

My question is because i'm between. 4 disks r= aid1, or RAID10 (I want redundancy anyway..). And as "raid 10" = =3D 1+ 0. I need to know raid0 performance to take a choice... I don't = need write speed, just read.

=C2=BFAnyone knows the true about this? =C2= =BFSomebody tried this?

Thanx a lot.!! Bytes= ! ;)

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