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Hi Heinz,
Concerning the partitioning support. I now feel that kpartx or (partx which could be made compatible) would be the way to go in stead of dmraid. So it would be a good idea to remove the partitioning support from dmraid. This will mean the package maintainer will need to make dmraid dependent on kpartx for it to work. One remark on this: I found that on Debian to make kpartx work with dmraid during boot, one needs to make some changes to the multipath-tools packages. On a side note: Why does mdadm support MBR and GPT? Concerning the usage of mdadm instead of dmraid. Me and probably and a large amount of AMD users will have a AMD chip-set which means a Promise FAKERAID controller. So in my idea I had two options update dmraid to work with the dm-raid target(probably the device-mapper target wrapper you are talking about) to setup my RAID-5 or add support for the Promise metadata format to mdadm. I picked the former as the code of dmraid look easier to understand. ;-) If you say that adding a super-promise.c to mdadm is doable, I could change my mind. Just one last question I never really got an answer to. Can one use mdadm on a dual boot system(MS and Linux) were the RAID partitions are shared? In other words will mdadm leave the metadata on the disks unchanged or in a state the the MS drivers can still recognize the RAID. Would it be an idea to clean-up dmraid? Remove what is not needed anymore, or does not fit the purpose of the tool. Kind regards, Mark-Willem Date: Thu, 19 Jul 2012 10:26:49 +0200 From: heinzm@xxxxxxxxxx To: ataraid-list@xxxxxxxxxx Subject: Re: Picking up development of dmraid On 07/18/2012 11:08 AM, Danny Wood wrote: Hi Mark-Willem Jansen Seconded WRT the niche market. It's usually only used by the people who run a dual boot with Windows as Mdadm is far superior for pure Linux installs. The later is exactly why things move to MD and eg. we're doing a device-mapper target wrapper to access the MD kernel runtime in order to make it accessible in LVM. Because the MD runtime has the long established field record it has, major FAKERAID OEMs decided to use it (namly Intel with their Intel Matrix RAID, isw in dmraid). mdadm gained external metadata format support along the lines of dmraid to allow for that and thus supports isw for long time now. As a result of that, Red Hat decided to not further develop dmraid. Actually we already asked publically, if dmraid is still mandatory to support the other metadata formats than DDF, Intel Matrix RAID and MD, which are supported by mdadm now anyway. No arguments it's still needed resulted from that so far.
There's no need to have code duplication for partitioinig support in another tool. For the record: the DOS partitioning support got added way back in time before kpartx addressed it (and never got pulled out). So use kpartx for activating partitionins on RAID sets. The most important question (as mentioned above) still persists though: is dmraid still needed or is any further development adequate to support the Adaptec, Highpoint, Jmicron, LSI, NVidia, Promise, Silicon Image and VIA metadata formats? Are they still being used that much in the field or are users just happy with dmraid access to those in their mixed Linux/Windows environments? Requirement for pure Linux environment is MD/LVM anyway. We better get field feedback which we didn't get so far to answer that question. Heinz
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