From mboxrd@z Thu Jan 1 00:00:00 1970 From: roger zhou Subject: Re: clustered MD - beyond RAID1 Date: Fri, 25 Dec 2015 16:47:14 +0800 Message-ID: <567D0292.6040606@suse.com> References: <56742652.5040304@nasa.gov> <87si2w66tm.fsf@notabene.neil.brown.name> <567850C4.30108@bnl.gov> <87bn9j4jhr.fsf@notabene.neil.brown.name> <56786EA4.2020209@bnl.gov> <8737uv4fz6.fsf@notabene.neil.brown.name> <5678A2B9.6070008@bnl.gov> <5678AC55.7070606@nasa.gov> <5678B693.40907@bnl.gov> Reply-To: Cluster Labs - All topics related to open-source clustering welcomed Mime-Version: 1.0 Content-Type: multipart/mixed; boundary="===============3687497246831613928==" Return-path: In-Reply-To: <5678B693.40907-IGkKxAqZmp0@public.gmane.org> List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Errors-To: users-bounces-iJOQKD3IPJ/s2ve5o0e2fw@public.gmane.org To: Tejas Rao , Aaron Knister Cc: NeilBrown , linux-raid-u79uwXL29TY76Z2rM5mHXA@public.gmane.org, Scott Sinno , users-iJOQKD3IPJ/s2ve5o0e2fw@public.gmane.org List-Id: linux-raid.ids This is a multi-part message in MIME format. --===============3687497246831613928== Content-Type: multipart/alternative; boundary="------------070607010406080709010009" This is a multi-part message in MIME format. --------------070607010406080709010009 Content-Type: text/plain; charset=windows-1252; format=flowed Content-Transfer-Encoding: 7bit On 12/22/2015 10:33 AM, Tejas Rao wrote: > On 12/21/2015 20:50, Aaron Knister wrote: > [...] >> >> I'm curious now, Redhat doesn't support SW raid failover? I did some >> googling and found this: >> >> https://access.redhat.com/solutions/231643 >> >> While I can't read the solution I have to figure that they're now >> supporting that. I might actually explore that for this project. > https://access.redhat.com/solutions/410203 > This article states that md raid is not supported in RHEL6/7 under any > circumstances, including active/passive modes. OCFS2 or GFS2(same for GPFS, as the shared filesystem) over a shared storage is a typical Cluster configuration for Linux High Availability. Where, Clustered LVM (cLVM) is supported by both SUSE and Redhat to do mirroring to protect the data. However, the performance loss is very big and make people not so happy about this clustered mirror solution. This is where the motivation for clustered MD solution comes from. With clustered md, this new solution could provide nearly the same performance as the native raid1. You may have interest to validate this from your lab with your configuration;) Cheers, Roger --------------070607010406080709010009 Content-Type: text/html; charset=windows-1252 Content-Transfer-Encoding: 7bit
On 12/22/2015 10:33 AM, Tejas Rao wrote:
On 12/21/2015 20:50, Aaron Knister wrote:

[...]

I'm curious now, Redhat doesn't support SW raid failover? I did some
googling and found this:

https://access.redhat.com/solutions/231643

While I can't read the solution I have to figure that they're now
supporting that. I might actually explore that for this project.
https://access.redhat.com/solutions/410203
This article states that md raid is not supported in RHEL6/7 under any circumstances, including active/passive modes.

OCFS2 or GFS2(same for GPFS, as the shared filesystem) over a shared storage is a typical Cluster configuration for Linux High Availability. Where, Clustered LVM (cLVM) is supported by both SUSE and Redhat to do mirroring to protect the data. However, the performance loss is very big and make people not so happy about this clustered mirror solution. This is where the motivation for clustered MD solution comes from.

With clustered md, this new solution could provide nearly the same performance as the native raid1. You may have interest to validate this from your lab with your configuration;)

Cheers,
Roger



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