On Thu, 5 Apr 2012, Craig Sanders <cas@taz.net.au> wrote:
ZFS can also do de-duping(**) but vast quantities of RAM & L2ARC required, on the order of 4-6GB RAM or more per TB of storage
http://configure.ap.dell.com/dellstore/config.aspx?oc=u421102au&c=au&l=en&s=... t110-2 If you have a need for 15k rpm SAS disks then you are limited to a maximum size of about 600G per disk. If you get a server like a Dell PowerEdge T110 then you have a maximum of 4 disks (1.8TB of RAID-5) and 32G of RAM. So using 7-11G of RAM to save some of that 1.8T of storage could be useful. There are a bunch of options from Dell for servers (and similar options from other companies) and the ratios of RAM to storage for most of the systems with internal disks such that if you want RAID-5 or RAID-6 of SAS disks then you can use 4-6G of RAM per TB of storage and still have plenty spare. Of course if you want to use large SATA disks with SSD and other forms of cache then things are totally different. -- My Main Blog http://etbe.coker.com.au/ My Documents Blog http://doc.coker.com.au/