geom/stripe/gstripe.8

.\" Copyright (c) 2004-2005 Pawel Jakub Dawidek <pjd@FreeBSD.org>
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.Dd May 21, 2004
.Dt GSTRIPE 8
.Os
.Sh NAME
.Nm gstripe
.Nd "control utility for striped devices"
.Sh SYNOPSIS
.Nm
.Cm create
.Op Fl v
.Op Fl s Ar stripesize
.Ar name
.Ar prov prov ...
.Nm
.Cm destroy
.Op Fl fv
.Ar name ...
.Nm
.Cm label
.Op Fl hv
.Op Fl s Ar stripesize
.Ar name
.Ar prov prov ...
.Nm
.Cm stop
.Op Fl fv
.Ar name ...
.Nm
.Cm clear
.Op Fl v
.Ar prov ...
.Nm
.Cm dump
.Ar prov ...
.Nm
.Cm list
.Nm
.Cm status
.Nm
.Cm load
.Nm
.Cm unload
.Sh DESCRIPTION
The
.Nm
utility is used for setting up a stripe on two or more disks.
The striped device can be configured using two different methods:
.Dq manual
or
.Dq automatic .
When using the
.Dq manual
method, no metadata are stored on the devices, so the striped
device has to be configured by hand every time it is needed.
The
.Dq automatic
method uses on-disk metadata to detect devices.
Once devices are labeled, they will be automatically detected and
configured.
.Pp
The first argument to
.Nm
indicates an action to be performed:
.Bl -tag -width ".Cm destroy"
.It Cm create
Set up a striped device from the given devices with specified
.Ar name .
This is the
.Dq manual
method and the stripe will not exist after a reboot (see
.Sx DESCRIPTION
above).
The kernel module
.Pa geom_stripe.ko
will be loaded if it is not loaded already.
.It Cm label
Set up a striped device from the given devices with the specified
.Ar name .
This is the
.Dq automatic
method, where metadata are stored in every device's last sector.
The kernel module
.Pa geom_stripe.ko
will be loaded if it is not loaded already.
.It Cm stop
Turn off an existing striped device by its
.Ar name .
This command does not touch on-disk metadata!
.It Cm destroy
Same as
.Cm stop .
.It Cm clear
Clear metadata on the given devices.
.It Cm dump
Dump metadata stored on the given devices.
.It Cm list
See
.Xr geom 8 .
.It Cm status
See
.Xr geom 8 .
.It Cm load
See
.Xr geom 8 .
.It Cm unload
See
.Xr geom 8 .
.El
.Pp
Additional options:
.Bl -tag -width ".Fl s Ar stripesize"
.It Fl f
Force the removal of the specified striped device.
.It Fl h
Hardcode providers' names in metadata.
.It Fl s Ar stripesize
Specifies size of stripe block in bytes.
The
.Ar stripesize
must be a multiple of the largest sector size of all the providers.
.It Fl v
Be more verbose.
.El
.Sh SYSCTL VARIABLES
The following
.Xr sysctl 8
variables can be used to control the behavior of the
.Nm STRIPE
GEOM class.
The default value is shown next to each variable.
.Bl -tag -width indent
.It Va kern.geom.stripe.debug : No 0
Debug level of the
.Nm STRIPE
GEOM class.
This can be set to a number between 0 and 3 inclusive.
If set to 0 minimal debug information is printed, and if set to 3 the
maximum amount of debug information is printed.
.It Va kern.geom.stripe.fast : No 0
If set to a non-zero value enable
.Dq "fast mode"
instead of the normal
.Dq "economic mode" .
Compared to
.Dq "economic mode" ,
.Dq "fast mode"
uses more memory, but it is much faster for smaller stripe sizes.
If enough memory cannot be allocated,
.Nm STRIPE
will fall back to
.Dq "economic mode" .
.It Va kern.geom.stripe.maxmem : No 13107200
Maximum amount of memory that can be consumed by
.Dq "fast mode"
(in bytes).
This
.Xr sysctl 8
variable is read-only and can only be set as a tunable in
.Xr loader.conf 5 .
.It Va kern.geom.stripe.fast_failed
A count of how many times
.Dq "fast mode"
has failed due to an insufficient amount of memory.
If this value is large, you should consider increasing the
.Va kern.geom.stripe.maxmem
value.
.El
.Sh EXIT STATUS
Exit status is 0 on success, and 1 if the command fails.
.Sh EXAMPLES
The following example shows how to set up a striped device from four disks with a
128KB stripe size for automatic configuration,
create a file system on it,
and mount it:
.Bd -literal -offset indent
gstripe label -v -s 131072 data /dev/da0 /dev/da1 /dev/da2 /dev/da3
newfs /dev/stripe/data
mount /dev/stripe/data /mnt
[...]
umount /mnt
gstripe stop data
gstripe unload
.Ed
.Sh COMPATIBILITY
The
.Nm
interleave is in number of bytes,
unlike
.Xr ccdconfig 8
which use the number of sectors.
A
.Xr ccdconfig 8
.Ar ileave
of
.Ql 128
is 64 KB (128 512B sectors).
The same stripe interleave would be specified as
.Ql 65536
for
.Nm .
.Sh SEE ALSO
.Xr geom 4 ,
.Xr loader.conf 5 ,
.Xr ccdconfig 8 ,
.Xr geom 8 ,
.Xr gvinum 8 ,
.Xr mount 8 ,
.Xr newfs 8 ,
.Xr sysctl 8 ,
.Xr umount 8
.Sh HISTORY
The
.Nm
utility appeared in
.Fx 5.3 .
.Sh AUTHORS
.An Pawel Jakub Dawidek Aq Mt pjd@FreeBSD.org