From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Date: Tue, 7 Sep 2004 11:15:07 +0200 From: Lars Ellenberg To: drbd-dev@lists.linbit.com Subject: Re: [Drbd-dev] Re: drbd in linux-ha cvs Message-ID: <20040907091507.GA3257@nudl> References: <20040906135609.GT11820@marowsky-bree.de> <20040906145237.GB28956@nudl> <200409070957.57371.philipp.reisner@linbit.com> Mime-Version: 1.0 Content-Type: text/plain; charset=iso-8859-1 Content-Disposition: inline Content-Transfer-Encoding: 8bit In-Reply-To: <200409070957.57371.philipp.reisner@linbit.com> List-Id: Coordination of development List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , On Tue, Sep 07, 2004 at 09:57:57AM +0200, Philipp Reisner wrote: > On Monday 06 September 2004 16:52, you wrote: > > waere es sinnvoll sowas zu haben: > > > > drbdadm dump_meta_data r0 (oder info oder wie immer wir das nennen wollen) > > > > output would be bash sourceable: > > GEN_COUNT=SOME:LONGER:STRING:WITH:NUMBERS:AND:STUFF > > LOCAL_STATE={Primary,Secondary} > > REMOTE_STATE=... > > CSTATE=... > > LOCAL_STORAGE=... > > > > > > name space clashes können so gelöst werden: > > eval `drbdadm info r0 | sed 's/^/DRBD_/'` > > > > müsste einmal vernünftig überlegt werden, welche informationen wir > > exportieren wollen, und wie die variablen genannt werden. > > wie drbdadm an die info rankommt ist seine sache. > > > > deal? > > > > Of course I am open to this idea. > > Ideas: > 1) We move the read_gc.pl/write_gc.pl to the user directory. > 2) Make them to one C program: drbdmeta > -> in the future the module never creates the meta data > block. One can use drbdmeta to create, read and > modify the drbdmeta block. drbdmeta refuses to write > to it as long as the module is loaded (configured). > 3) drbdadm is the nice frontend to drbdmeta is it is to > drbdsetup. I don't want to make it easier to write generation counts. heartbeat-TNG may have use for knowing the current ones, though. > Currently we have these drbdadm commands that are not displayed > at the usage output: > > { "sh-resources", sh_resources,0 ,0,0 }, > { "sh-mod-parms", sh_mod_parms,0 ,0,0 }, > { "sh-dev", sh_dev, 0 ,0,1 }, > { "sh-ll-dev", sh_ll_dev, 0 ,0,1 }, > { "sh-md-dev", sh_md_dev, 0 ,0,1 }, > { "sh-md-idx", sh_md_idx, 0 ,0,1 } > > ... and we have state and cstate: > > { "state", adm_generic_s,"state" ,1,1 }, > { "cstate", adm_generic_s,"cstate" ,1,1 }, > > with the current interface you would do: > > CSTATE=$(drbdadm cstate r0) > LOCAL_STATE=$( $DRBDADM state $RES 2> /dev/null ) > LOCAL_STATE=${LOCAL_STATE%/*} > LOCAL_STORAGE= $(drbdadm sh-ll-dev r0) > ... > > With the current interface we have a lot of calls to drbdadm, so lets > have a look at the performance: > > root@bloody:~/drbd07/user# time drbdadm sh-ll-dev r0 > /dev/hdc1 > > real 0m0.170s > user 0m0.059s > sys 0m0.111s > > ... Quite slow! > > > So I disabled "verify_ips()". [ should probabely be really disabled. ] or only enabled with "verify config" or something like that. > root@bloody:~/drbd07/user# time ./drbdadm sh-ll-dev r0 > /dev/hdc1 > > real 0m0.006s > user 0m0.001s > sys 0m0.005s > > ... now a call to drbdadm is as cheap as expected. > > So with continuing the current way of doing things, I would > extend the interface in this way: > > drbdadm md-set-gc 1:2:3:4:5:6 r0 > drbdadm md-get-gc 1:2:3:4:5:6 r0 > drbdadm md-get/set-{la-size|consistent|etc...} resources.... > drbdadm md-create r0 > > I rather prefer the current way, since it is also language > agnostic. In perl: $local_storage = `drbdadm sh-ll-dev r0`; > While the proposed interface is tied to bash. the point was to have an easy way to _read_ all available information in a well defined way in one chunk. and having it in k=v form makes it direktly useable by bash, and easily useable by perl: $_=`drbdadm info r0`; %drbdinfo = /^(.*?)=(.*?)$/mg; # :-) I do NOT want to make it easy to _modify_ on-disk meta data. if it is too easy (or even documented), people will screw up, and blame us for it. lge