----- "Brandon High" <bh...@freaks.com> skrev: > On Sun, Jun 6, 2010 at 3:26 AM, Roy Sigurd Karlsbakk > <r...@karlsbakk.net> wrote: > > ----- "Brandon High" <bh...@freaks.com> skrev: > >> Decreasing the block size increases the size of the dedup table > >> (DDT). > >> Every entry in the DDT uses somewhere around 250-270 bytes. > > > > Are you sure it's that high? I was told it's ~150 per block, or > ~1,2GB per terabytes of storage with only 128k blocks > > No, that's the number that stuck in my head though. > > Even if the DDT entry is smaller, the point I was making doesn't > change. A smaller record size will increase dedup performance at the > cost of a larger DDT. Once the DDT is too large to fit in the ARC, > performance tanks.
I cannot but agree with that - if you want to use dedup, (a) wait for the next release (since there are several rather bad bugs in 134) and (b) get a truckload of SSDs for L2ARC to make the system usable. Vennlige hilsener / Best regards roy -- Roy Sigurd Karlsbakk (+47) 97542685 r...@karlsbakk.net http://blogg.karlsbakk.net/ -- I all pedagogikk er det essensielt at pensum presenteres intelligibelt. Det er et elementært imperativ for alle pedagoger å unngå eksessiv anvendelse av idiomer med fremmed opprinnelse. I de fleste tilfeller eksisterer adekvate og relevante synonymer på norsk. _______________________________________________ zfs-discuss mailing list zfs-discuss@opensolaris.org http://mail.opensolaris.org/mailman/listinfo/zfs-discuss
