In the last episode (Nov 18), Brian Candler said: > Vinum's manpage makes my head spin. I was wondering if anyone had > considered implementing something a bit more straightforward and also > more dynamic. > > Suppose you: > > (1) Divide all your disks up-front into equal sized chunks, say 4MB. > > (2) Use an indirection table to map each volume into an arbitary set of > these chunks across all available disks. > > (3) Store the indirection table at the end of a partition, as other > GEOM modules do for their metadata, and cache it in RAM. > > (e.g. a 160GB drive, divided into 4MB blocks, each of which has a > 32-bit indirection table entry, would require only 160KB of > indirection table) AIX does something similar in its volume manager. A volume group consists of a number of disks, split into equal-sized partitions (256MB is the default I think). Logical volumes reside in the volume group, and are composed of multiple partitions. Each LV can have its own raid/mirror characteristics separate from others, and can be grown, mirrored, or otherwise modified online. http://publib.boulder.ibm.com/infocenter/pseries/topic/com.ibm.aix.doc/aixbman/admnconc/logical_vol.htm http://publib.boulder.ibm.com/infocenter/pseries/topic/com.ibm.aix.doc/aixbman/prftungd/diskperf.htm -- Dan Nelson dnelson_at_allantgroup.comReceived on Fri Nov 18 2005 - 16:36:01 UTC
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