On Sat, 29 Nov 2008, Ray Clark wrote: > > [1] You said "zfs uses large amounts of memory for its cache". If I > understand correctly, it is not that it uses large amounts, it is > that it uses all memory available. If this is an accurate picture, > then it should be just as happy with 128MB as it is with 4GB. The > result would simply be less of a cache/buffer between clients and > the physical disk. It also seems like any congestion should show up
Memory is about 10,000 times faster than disk. Why should it be just as happy with vastly less memory? > [2] Regarding zfs vs. nfs, the reference talks about unneeded cache > flushes dragging down throughput to NVRAM buffered disks. The > flushes were designed for physical rotating disks. I am using > physical, rotating disks, so it seems like the changes that they > suggest for NVRAM buffered disks would not be appropriate for me, > and that the default behavior designed for physical rotating disks > would be what I want. What am I missing? Most NVRAM buffered disks do use caching. The question is how reliably unflushed data will be stored after power loss. FLASH devices definitely use a cache buffer since writes to FLASH are actually pretty slow (often slower than rotating media) and the FLASH blocksize is typically larger than the write blocksize. Bob ====================================== Bob Friesenhahn [EMAIL PROTECTED], http://www.simplesystems.org/users/bfriesen/ GraphicsMagick Maintainer, http://www.GraphicsMagick.org/ _______________________________________________ zfs-discuss mailing list zfs-discuss@opensolaris.org http://mail.opensolaris.org/mailman/listinfo/zfs-discuss
