> From: zfs-discuss-boun...@opensolaris.org [mailto:zfs-discuss- > boun...@opensolaris.org] On Behalf Of Roy Sigurd Karlsbakk > > > Even *with* an L2ARC, your memory requirements are *substantial*, > > because the L2ARC itself needs RAM. 8 GB is simply inadequate for your > > test. > > With 50TB storage, and 1TB if L2ARC, with no dedup, what amount of ARC > would you would you recommeend?
Without dedup and without L2ARC, the amount of ram you require is unrelated to amount of storage you have. Your ram requirement depends on what applications you run. Any excess ram you have will be used for ARC (that is, L1 ARC) and therefore used to benefit performance. So excess ram is always good. Do not be a cheapskate with ram. Regardless of whether you use ZFS, or any other filesystem, or any other OS, even windows or linux. Excess ram is always a good thing. It always improves stability and improves performance. If you are using a laptop and not serving anything and performance is not a major concern and you're free to reboot whenever you want, then you can survive on 2G of ram. But a server presumably DOES stuff and you don't want to reboot frequently. I'd recommend 4G minimally, 8G standard, and if you run any applications (databases, web servers, symantec products) then add more. And if you use dedup, or l2arc, then add more. > And then, _with_ dedup, what would you recommemend? If you have dedup enabled, add slightly under 3G ram for every 1TB unique data in your pool on top of whatever you've selected for your base ram configuration. _______________________________________________ zfs-discuss mailing list zfs-discuss@opensolaris.org http://mail.opensolaris.org/mailman/listinfo/zfs-discuss
