It needn't be all that difficult. Consider the following: you have a block layer driver which performs the following duties: it manages a pool of N block devices it exposes a portion of that storage as a single block device the unexposed portion goes towards parity (in the vein of providing at least N bits of parity protection) the level of parity protection is applied to each block of size X. For example a 64K block might consist of 48K of data and 16K of parity. on top of that, the data+parity could be mirrored on N other devices, anywhere, so long as it is mirrored on at least M other devices. I'm just kinda thinking out loud. The duplicate block stuff could just as easily be an md1 or md10 layer, so a new raid level might only have to handle the parity stuff. On Mon, Jan 19, 2009 at 2:18 PM, Greg Freemyer <greg.freemyer@xxxxxxxxx> wrote: > On Mon, Jan 19, 2009 at 3:00 PM, Jon Nelson > <jnelson-linux-raid@xxxxxxxxxxx> wrote: >> I guess what I'd like to see more than anything else is not raid5 or >> raid6 but raidN where N can be specified at the start and grown. While >> I'm not a fan of ZFS's rulebreaking one thing it does (or claims to >> do) strikes me as "the future" - the ability to specify X protection >> bits and to increase or decrease X as needs see fit. It also strikes >> me that there are several ways to do this but fundamentally it boils >> down to "we don't trust our drives anymore and there we wish to >> protect our data against their failure". Given 5 or 10 or 50 drives >> how does one really protect their data effectively and allow their >> data pool to grow without large quantities of hoop-jumping? >> >> I'd really like to see a re-thinking of data protection (parity or >> data duplication) at the block layer - it need not be RAID as we know >> it but IMO something has to be done - rapidly do we near the >> precipice! > > If I understand what your saying, HP started supporting "Raid > Equivalent" protection in some of their storage arrays years ago. > > You simply put a bunch of disk drives in the unit, then tell you want > a 50GB logical volume with Raid 5 equivalent protection, etc. > > I think it might for example allocate 10 GB from each of 6 disk > drives. (ie. 5 for data + 1 for parity). > > Then you ask for 30 GB with raid 10 equivalent protection and it might > allocate 10GB more from those same 6 drives. > > Then you go back and increase the size of th 50GB raid5 and it would > allocate more space on the drives as required, but always ensuring the > data was protected at least at raid5 levels. > > I sort of thought of it as an integrated LVM and Raid manager. > > I suspect putting that together is a pretty large amount of effort. > > Greg > -- > Greg Freemyer > Litigation Triage Solutions Specialist > http://www.linkedin.com/in/gregfreemyer > First 99 Days Litigation White Paper - > http://www.norcrossgroup.com/forms/whitepapers/99%20Days%20whitepaper.pdf > > The Norcross Group > The Intersection of Evidence & Technology > http://www.norcrossgroup.com > -- Jon -- To unsubscribe from this list: send the line "unsubscribe linux-raid" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
