Note: "permalinks" may not be as permanent as we would like,
direct links of old sources may well be a few messages off.
Are you aware that MD RAID1 supports write intent bitmap that allows the resync of only the changed blocks since the last sync? See https://raid.wiki.kernel.org/index.php/Write-intent_bitmap. Radu On Thu, Jun 26, 2014 at 4:12 PM, Allen Chen <achen at harbourfrontcentre.com> wrote: > On 6/26/2014 6:00 AM, drbd-user-request at lists.linbit.com wrote: > >> Send drbd-user mailing list submissions to >> drbd-user at lists.linbit.com >> >> To subscribe or unsubscribe via the World Wide Web, visit >> http://lists.linbit.com/mailman/listinfo/drbd-user >> or, via email, send a message with subject or body 'help' to >> drbd-user-request at lists.linbit.com >> >> You can reach the person managing the list at >> drbd-user-owner at lists.linbit.com >> >> When replying, please edit your Subject line so it is more specific >> than "Re: Contents of drbd-user digest..." >> >> >> Today's Topics: >> >> 1. Re: Sync to the same IP (Lars Ellenberg) >> >> >> ---------------------------------------------------------------------- >> >> Message: 1 >> Date: Thu, 26 Jun 2014 11:11:23 +0200 >> From: Lars Ellenberg <lars.ellenberg at linbit.com> >> Subject: Re: [DRBD-user] Sync to the same IP >> To: drbd-user at lists.linbit.com >> Message-ID: <20140626091123.GH17123 at soda.linbit> >> Content-Type: text/plain; charset=us-ascii >> >> On Thu, Jun 19, 2014 at 01:23:56AM +0200, Alexey Orishko wrote: >> >>> Hi all, >>> >>> I got recently across DRBD and it looks like a cool stuff. >>> I wonder if someone could clarify for me if it is possible to >>> configure DRBD to sync one block device to another block device on the >>> same host? >>> >> yes you can >> (example of how to do that was provided in the thread already; >> yes you can use 127.0.0.1; no you don't need ip aliases) >> >> No, I don't think that's a good idea. >> >> On Sun, Jun 22, 2014 at 10:56:21PM +0200, Alexey Orishko wrote: >> >>> On Sun, Jun 22, 2014 at 7:38 PM, Bret Mette <bret.mette at dbihosting.com> >>> wrote: >>> >>>> I would still like to know what the purpose is for this. You're picking >>>> the >>>> brains of the community for a solution to your problem, it would be >>>> nice to >>>> give a little back and share the backstory about that problem. >>>> >>> I want to figure out if DRBD is suitable for making a second copy of >>> backup disk without stopping client. >>> >> Explain to me why md raid1 won't do what you want. >> Same question to the >> "Someone talked about this on some Amazon event, >> and I want to do what he thinks is cool" fraction. >> >> This is host based mirroring. >> md raid1 is meant to do that. >> Why not use it? >> >> Oh, so you want it async... >> Did you know about mdadm "write-mostly" and "write-behind"? >> >> It's not that DRBD cannot do it. >> It's just that I think it is the wrong tool for the job. >> So please explain to me why you think otherwise. >> >> Lars >> >> Hi Lars, > > Here is my explanation to use DRBD instead of md raid1: > for md raid1, if one member is physically removed from the machine, and > after you reconnect the same disk to md raid1, MD will re-sync everything > to it. It takes much more time. > for DRBD, if the second disk is removed from the machine, and after you > reconnect the same disk to DRBD, DRBD will sync whatever has been changed. > It take less time than MD raid1. > > So I need someone to confirm DRBD will work with primary and second nodes > on the same machine. > > Thanks, > Allen > > _______________________________________________ > drbd-user mailing list > drbd-user at lists.linbit.com > http://lists.linbit.com/mailman/listinfo/drbd-user > -------------- next part -------------- An HTML attachment was scrubbed... URL: <http://lists.linbit.com/pipermail/drbd-user/attachments/20140627/72b0bba1/attachment.htm>