On Jan 20, 2011, at 11:18 AM, Eugen Leitl wrote: >>> I'd expect more than 105290K/s on a sequential read as a peak for a single >>> drive, let alone a striped set. The system has a relatively decent CPU, >>> however only 2GB memory, do you think increasing this to 4GB would >>> noticeably affect performance of my zpool? The memory is only DDR1. >> >> 2GB or 4GB of RAM + dedup is a recipe for pain. Do yourself a favor, turn >> off dedup >> and enable compression. > > Assuming 4x 3 TByte drives and 8 GByte RAM, and a lowly dual-core 1.3 GHZ > AMD Neo, should I do the same? Or should I even not bother with compression? > The data set is a lot of scanned documents, already compressed (TIF and PDF). > I presume the incidence of identical blocks will be very low under such > circumstances.
This would seem very unlikely to benefit from dedup (unless you cp the individual files to multiple directories). But if you are just keeping lots of scans the odds of a given block being identical to a lot of other ones seem low. The thing about compression is it is easy to test out (whereas dedup can be more painful to test when it doesn't work out). So you might as well try, but it would seem like dedup is a waste of time and might well cause a lot of headaches. Good luck, Ware _______________________________________________ zfs-discuss mailing list zfs-discuss@opensolaris.org http://mail.opensolaris.org/mailman/listinfo/zfs-discuss
