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Fix markup and some typos.

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This commit is contained in:
Ruslan Ermilov 2006-04-14 09:20:25 +00:00
parent c943ffcc29
commit d5bd01d213
Notes: svn2git 2020-12-20 02:59:44 +00:00 
svn path=/head/; revision=157748
2 changed files with 83 additions and 27 deletions
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19
sbin/ccdconfig/ccdconfig.8
View File

@ -130,7 +130,10 @@ The component devices need to name partitions of type
as shown by
.Xr disklabel 8 ) .
.Pp
If you want to use the Linux md(4) compatibility mode, please be sure
If you want to use the
.Tn Linux
.Xr md 4
compatibility mode, please be sure
to read the notes in
.Xr ccd 4 .
.Sh FILES
@ -165,13 +168,19 @@ and assigned to ccd0.
# ccdconfig ccd0 128 CCDF_MIRROR /dev/da8s2 /dev/da9s3
.Ed
.Pp
The following are matching commands in Linux and FreeBSD to create a
raid-0 in Linux and read it from FreeBSD.
The following are matching commands in
.Tn Linux
and
.Fx
to create a RAID-0 in
.Tn Linux
and read it from
.Fx .
.Bd -literal
# Create a raid-0 on Linux:
# Create a RAID-0 on Linux:
mdadm --create --chunk=32 --level=0 --raid-devices=2 /dev/md0 \\
/dev/hda1 /dev/hdb1
# Make the raid-0 just created available on FreeBSD:
# Make the RAID-0 just created available on FreeBSD:
ccdconfig -c /dev/ccd0 32 linux /dev/ad0s1 /dev/ad0s2
.Ed
.Pp

91
share/man/man4/ccd.4
View File

@ -173,33 +173,80 @@ You cannot replace a disk in a mirrored
.Nm
partition without first backing up the partition, then replacing the disk,
then restoring the partition.
.Ss Linux compatibility
The Linux compatibility mode does not try to read the label that Linux'
md(4) driver leaves on the raw devices. You will have to give the order
of devices and the interleave factor on your own. When in Linux
compatibility mode, ccd will convert the interleave factor from Linux
terminology. That means you give the same interleave factor that you
gave as chunk size in Linux.
.Ss Linux Compatibility
The
.Tn Linux
compatibility mode does not try to read the label that
.Tn Linux Ns '
.Xr md 4
driver leaves on the raw devices.
You will have to give the order
of devices and the interleave factor on your own.
When in
.Tn Linux
compatibility mode,
.Nm
will convert the interleave factor from
.Tn Linux
terminology.
That means you give the same interleave factor that you
gave as chunk size in
.Tn Linux .
.Pp
If you have a Linux md(4) device in "legacy" mode, do not use the
CCD_LINUX flag in
If you have a
.Tn Linux
.Xr md 4
device in
.Dq legacy
mode, do not use the
.Dv CCDF_LINUX
flag in
.Xr ccdconfig 8 .
Use the CCD_NO_OFFSET flag instead. In that case you have to convert
the interleave factor on your own, usually it is Linux' chunk size
multiplied by two.
Use the
.Dv CCDF_NO_OFFSET
flag instead.
In that case you have to convert
the interleave factor on your own, usually it is
.Tn Linux Ns '
chunk size multiplied by two.
.Pp
Using a Linux raid this way is potentially dangerous and can destroy
the data in there. Since FreeBSD does not read the label used by
Linux, changes in Linux might invalidate the compatibility layer.
Using a
.Tn Linux
RAID this way is potentially dangerous and can destroy
the data in there.
Since
.Fx
does not read the label used by
.Tn Linux ,
changes in
.Tn Linux
might invalidate the compatibility layer.
.Pp
However, using this is reasonably safe if you test the compatibility
before mounting a raid read-write for the first time. Just using
ccdconfig without mounting does not write anything to the Linux raid.
Then you do a fsck.ex2fs on the ccd device using the -n flag. You can
mount the filesystem readonly to check files in there. If all this
works, it is unlikely that there is a problem with ccd. Keep in mind
that even when the Linux compatibility mode in ccd is working
correctly, bugs in FreeBSD's ex2fs implementation would still destroy
before mounting a RAID read-write for the first time.
Just using
.Xr ccdconfig 8
without mounting does not write anything to the
.Tn Linux
RAID.
Then you do a
.Nm fsck.ext2fs Pq Pa ports/sysutils/e2fsprogs
on the
.Nm
device using the
.Fl n
flag.
You can mount the file system read-only to check files in there.
If all this works, it is unlikely that there is a problem with
.Nm .
Keep in mind that even when the
.Tn Linux
compatibility mode in
.Nm
is working correctly, bugs in
.Fx Ap s
.Nm ex2fs
implementation would still destroy
your data.
.Sh WARNINGS
If just one (or more) of the disks in a