Matthew Ahrens writes: > Jeremy Teo wrote: > > Would it be worthwhile to implement heuristics to auto-tune > > 'recordsize', or would that not be worth the effort? > > Here is one relatively straightforward way you could implement this. > > You can't (currently) change the recordsize once there are multiple > blocks in the file. This shouldn't be too bad because by the time > they've written 128k, you should have enough info to make the choice. > In fact, that might make a decent algorithm: > > * Record the first write size (in the ZPL's znode) > * If subsequent writes differ from that size, reset write size to zero > * When a write comes in past 128k, see if the write size is still > nonzero; if so, then read in the 128k, decrease the blocksize to the > write size, fill in the 128k again, and finally do the new write. > > Obviously you will have to test this algorithm and make sure that it > actually detects the recordsize on various databases. They may like to > initialize their files with large writes, which would break this. If > you have to change the recordsize once the file is big, you will have to > rewrite everything[*], which would be time consuming. > > --matt >
Oracle will typically create it's files with 128K writes not recordsize ones. -r _______________________________________________ zfs-discuss mailing list zfs-discuss@opensolaris.org http://mail.opensolaris.org/mailman/listinfo/zfs-discuss
