Date: Fri, 3 Nov 2000 02:12:46 +0100 (CET) From: Marius Bendiksen <mbendiks@eunet.no> To: Matt Dillon <dillon@earth.backplane.com> Cc: Alfred Perlstein <bright@wintelcom.net>, Randell Jesup <rjesup@wgate.com>, arch@FreeBSD.ORG Subject: Re: Like to commit my diskprep Message-ID: <Pine.BSF.4.05.10011030209060.14073-100000@login-1.eunet.no> In-Reply-To: <200011022135.eA2LZA740940@earth.backplane.com>
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> Indirect blocks aren't relevant if you are using a large block size, > because there are few enough of them the OS has no problem caching > them. The problem is related to highly random access, as the indirect blocks will tend to get pushed out of the cache on occasion, requiring multiple seeks when the file is being accessed. Using extents will solve this. > 32K block size 4MB Note that these 4MB are better spent on caching real data than they are on compensating for the absence of extents in the FFS inode. > It becomes somewhat more of an issue for a terrabyte-sized database, > but still no biggy considering the memory you can get these days. I reiterate the above point. The kind of memory in question here is really way over the top, compared to the 8/16 bytes required to hold an extent reference and the bit to indicate that the inode uses such. > A raw device will still be better, but not by much. "But not by much" depends on the actor operating upon it, amongst other things. Marius To Unsubscribe: send mail to majordomo@FreeBSD.org with "unsubscribe freebsd-arch" in the body of the message
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