Date: Thu, 13 Dec 2001 15:32:22 -0600 (CST) From: Ryan Thompson <ryan@sasknow.com> To: Sam Suh <sam@bigstudios.com> Cc: <freebsd-questions@FreeBSD.ORG> Subject: Re: Disk space shrink? Message-ID: <20011213152346.S94620-100000@catalyst.sasknow.net> In-Reply-To: <3C190E14.E0442E28@bigstudios.com>
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Sam Suh wrote to freebsd-questions@FreeBSD.ORG: > Hi, everyone. > > [...] > on other 3; hence 186 GB. Now, I have it on the freebsd, it only reports > 164 GB of free space. Why is it happening? In a installation phase, I > have selected da0a drive and selected use entire drive option. > [...] Hi Sam, Most likely what you are experiencing here is the "minfree" property of FFS, which, by default, reserves 8% of your filesystem space to reduce fragmentation. root can write to the unused 8%, so if a root process fills up a filesystem, you'll typically see 108% used... which usually begs a lot of questions. :-) Anyways, on a filesystem of this size, minfree does NOT need to be set at 8%. You can use tunefs(8) to safely reduce it to 5%. Any lower, and the kernel will optimize writes for space, which will give you a performance hit. Some time ago, I wrote a patch for the filesystem code which will allow you to reduce the minfree setting to below 5% without the kernel optimizing for time. Let me know if you're interested, and I'll dig it up. Also, you are probably wasting a significant amount of space with free inodes. On a filesystem of this size, you will have, by default, WAY more inodes than you need. (inode density, by default, is one inode per 4K..) Check the output of df -i to see how many inodes you have available. You should be shocked. :-) You'll have to remake the filesystem to reduce this... use the -i option to newfs and specify a much higher value for bytes per inode. - Ryan -- Ryan Thompson <ryan@sasknow.com> Network Administrator, Accounts SaskNow Technologies - http://www.sasknow.com #106-380 3120 8th St E - Saskatoon, SK - S7H 0W2 Tel: 306-664-3600 Fax: 306-664-1161 Saskatoon Toll-Free: 877-727-5669 (877-SASKNOW) North America To Unsubscribe: send mail to majordomo@FreeBSD.org with "unsubscribe freebsd-questions" in the body of the message
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