svn commit: r235265 - head/share/man/man7
Ulrich Spoerlein
uqs at FreeBSD.org
Fri May 11 10:13:34 UTC 2012
Author: uqs
Date: Fri May 11 10:13:34 2012
New Revision: 235265
URL: http://svn.freebsd.org/changeset/base/235265
Log:
Stop lying about default UFS blocksizes.
This catches up with the year-old change to default blocksizes. Also
reduce the variants of spelling gigabyte from 3 down to 2 (GB and GiB).
Suggested by: arundel (about a year ago now ...)
Modified:
head/share/man/man7/tuning.7
Modified: head/share/man/man7/tuning.7
==============================================================================
--- head/share/man/man7/tuning.7 Fri May 11 09:46:17 2012 (r235264)
+++ head/share/man/man7/tuning.7 Fri May 11 10:13:34 2012 (r235265)
@@ -23,7 +23,7 @@
.\"
.\" $FreeBSD$
.\"
-.Dd October 16, 2010
+.Dd May 11, 2012
.Dt TUNING 7
.Os
.Sh NAME
@@ -148,15 +148,15 @@ If you do not use ports all that much an
system source
.Pq Pa /usr/src
on the machine, you can get away with
-a 1 gigabyte
+a 1 GB
.Pa /usr
partition.
However, if you install a lot of ports
(especially window managers and Linux-emulated binaries), we recommend
-at least a 2 gigabyte
+at least a 2 GB
.Pa /usr
and if you also intend to keep system source
-on the machine, we recommend a 3 gigabyte
+on the machine, we recommend a 3 GB
.Pa /usr .
Do not underestimate the
amount of space you will need in this partition, it can creep up and
@@ -218,22 +218,22 @@ and
.Em cylinders/group .
.Pp
.Fx
-performs best when using 8K or 16K file system block sizes.
-The default file system block size is 16K,
+performs best when using 16K or 32K file system block sizes.
+The default file system block size is 32K,
which provides best performance for most applications,
with the exception of those that perform random access on large files
(such as database server software).
Such applications tend to perform better with a smaller block size,
although modern disk characteristics are such that the performance
gain from using a smaller block size may not be worth consideration.
-Using a block size larger than 16K
+Using a block size larger than 32K
can cause fragmentation of the buffer cache and
lead to lower performance.
.Pp
The defaults may be unsuitable
for a file system that requires a very large number of i-nodes
or is intended to hold a large number of very small files.
-Such a file system should be created with an 8K or 4K block size.
+Such a file system should be created with an 4K, 8K, or 16K block size.
This also requires you to specify a smaller
fragment size.
We recommend always using a fragment size that is 1/8
@@ -256,13 +256,13 @@ Do not use this option
unless you are actually storing large files on the partition, because if you
overcompensate you can wind up with a file system that has lots of free
space remaining but cannot accommodate any more files.
-Using 32768, 65536, or 262144 bytes/i-node is recommended.
+Using 65536, 131072, or 262144 bytes/i-node is recommended.
You can go higher but
it will have only incremental effects on
.Xr fsck 8
recovery times.
For example,
-.Dq Li "newfs -i 32768 ..." .
+.Dq Li "newfs -i 65536 ..." .
.Pp
.Xr tunefs 8
may be used to further tune a file system.
@@ -525,8 +525,8 @@ sysctl governs VFS read-ahead and is exp
to pre-read if the heuristics algorithm decides that the reads are
issued sequentially.
It is used by the UFS, ext2fs and msdosfs file systems.
-With the default UFS block size of 16 KiB, a setting of 32 will allow
-speculatively reading up to 512 KiB.
+With the default UFS block size of 32 KiB, a setting of 64 will allow
+speculatively reading up to 2 MiB.
This setting may be increased to get around disk I/O latencies, especially
where these latencies are large such as in virtual machine emulated
environments.
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