Andree Leidenfrost said on Sat, Apr 29, 2006 at 05:32:55PM +1000: > Please find attached a patch that implements mdadm support whilst fully > retaining raidtools2 support.
Many thanks for your work in this Andree ! > With the changes detailed in the patch, I > have just successfully archived and restored a RAID1 and a RAID0 array > consisting of two drives each on Debian sid amd64, but I expect all > Linux distribution with mdadm to work as well (famous last words ;-) ). Great ! > After much going back and forth I have decided to extend what is already > there rather than recode much of the RAID functionality. The reasons are > mainly that I have only limited time and wanted results rather sooner > than later but even more so that I didn't want to change the raidtools2 > side of things because I can't/won't test this and I didn't want to > spend any effort on raidtools2 because it's officially deprecated (cf. > http://people.redhat.com/mingo/raidtools/). No problem. That's a wise decision I think. > With this said, the patch utilises existing capabilities for > parsing /proc/mdstat and for reading and writing /etc/raidtab. mdadm > works without a config file and even 'mdadm --detail --scan --verbose' > does not give all the (relevant) information that can be gathered from > mdstat. I could have come up with a new file (format), but I think > raidtab is fine (it shouldn't be in /etc really). I am introducing a new > function create_raid_device_via_mdadm() that will create a single RAID > array using mdadm and that gets called in format_device() in case mkraid > cannot be found. Same goes for 'mdadm -S' versus raidstop. An equivalent > for raidstart is not really required as 'mdadm --create' starts the > array straight away. > > There are limitations (pre-existing, not introduced by my changes): > - chunk size is hard coded to 4k Onc my set of conf files work, please remind us to put that in it. > - spare devices are ignored > - the parity algorithm is ignored > - multipath is not supported Ok. > To overcome these limitations, I will need to change some data > structures and expand the mdstat parser - in fact, I have already > written an experimental stand-alone parser for this purpose. I'm not > sure whether multipath is worth it; it is not even really a RAID level. No, but it's extremely useful for HA solutions. So if it's not a big effort, I'd like to see it one day. > Further, I had to include a few more modules for RAID in mindi and init > needed a little change. No pb. I'll commit those changes right now, as they are obvious > Finally, device mapper is not supported. I understand you are working on > this, so I haven't looked into it. Well I'll work on it, when I'm done with all the other patches I have to integrate (internationalization !!! done by an old relative, and also Labeled swap fs). It won't be in 2.0.8, but in the next, I hope, which should be 2.2.0 > It would be great if you could let me know what you think, in particular > whether you'd be sufficiently happy for this to go into the next stable > version. patch mindi: taken and applied. patch init: I have a question: You're testing first raidstart, and then assume that it's lvmv1 What about if both tools were installed ? Couldn't we get it more surely from another parameter ? Shouldn't we store it and pass it throught our conf file to init ? No problem, OTOH with the patch itself patch mondo-prep.c : when you use asprintf, the devices string is allocated. So before re-using it, you need to call paranoid_free on it. If not, we're creating memory leaks. In your case, you need 2 variables. Take an example in trunk to see how to deal with it. You also have the same problem with program. That's why it takes time to do that in trunk :-)) Maybe the sync could also be kept for mdadm ? Just to let time to the system to flush al the buffers. I would take the opportunity that you test mkraid vs mdadm to create an option somewhere that we could use in init. WDYT ? Greetings, Bruno. -- Linux Profession Lead EMEA / Open Source Evangelist \ HP C&I EMEA IET http://www.mondorescue.org / HP/Intel Solution Center \ http://hpintelco.net Des infos sur Linux? http://www.HyPer-Linux.org http://www.hp.com/linux La musique ancienne? http://www.musique-ancienne.org http://www.medieval.org
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