metasync(1M)						  System Administration Commands					      metasync(1M)

NAME

       metasync - handle metadevice resync during reboot

SYNOPSIS

       /usr/sbin/metasync -h

       /usr/sbin/metasync [-s setname] [buffer_size] metadevice

       /usr/sbin/metasync [-s setname] -r [buffer_size]

       /usr/sbin/metasync -p metadevice

       /usr/sbin/metasync -c metadevice

DESCRIPTION

       The  metasync  command  starts a resync operation on the specified metadevice. All components that need to be resynced are resynced. If the
       system crashes during a RAID5 initialization, or during a RAID5 resync, either  an  initialization  or  resync  restarts  when  the  system
       reboots.

       Applications are free to access a metadevice at the same time that it is being resynced by metasync. Also, metasync performs the copy oper-
       ations from inside the kernel, which makes the utility more efficient.

       Use the -r option in boot scripts to resync all possible submirrors.

OPTIONS

       The following options are supported:

       -c metadevice	Cancels the resync that is in progress on the specified metadevice. The resync will be stopped at its  current	point  and
			can be resumed by running the "metasync metadevice" command. This option only applies to RAID1 volumes.

       -h		Displays usage message.

       -p metadevice	Regenerates parity information for RAID5 metadevices.

       -s setname	Specifies  the	name of the diskset on which metasync will work. Using the -s option will cause the command to perform its
			administrative function within the specified diskset. Without this option, the command will perform its function on  local
			metadevices.

       -r		Specifies  that the metasync command handle special resync requirements during a system reboot. metasync -r should only be
			invoked from the svc:/system/mdmonitor service. The metasync command only  resyncs  those  metadevices	that  need  to	be
			resynced. metasync schedules all the mirror resyncs according to their pass numbers.

			To override the default buffer_size value used by the svc:/system/mdmonitor service, you can edit /etc/system to specify:

			  set md_mirror:md_resync_bufsz = 2048

			so that resyncs occur as quickly as possible.

OPERANDS

       buffer_size    Specifies  the size (number of 512-byte disk blocks) of the internal copy buffer for the mirror resync. The size defaults to
		      1024 512-byte disk blocks. It can be no more than 2048 blocks. For best performance (quickest  completion  of  the  resync),
		      2048 blocks is the recommended size.

EXIT STATUS

       The following exit values are returned:

       0     Successful completion.

       >0    An error occurred.

ATTRIBUTES

       See attributes(5) for descriptions of the following attributes:

       +-----------------------------+-----------------------------+
       |      ATTRIBUTE TYPE	     |	    ATTRIBUTE VALUE	   |
       +-----------------------------+-----------------------------+
       |Availability		     |SUNWmdu			   |
       +-----------------------------+-----------------------------+

SEE ALSO

       mdmonitord(1M),	metaclear(1M),	metadb(1M),  metadetach(1M),  metahs(1M),  metainit(1M),  metaoffline(1M),  metaonline(1M), metaparam(1M),
       metarecover(1M),  metarename(1M),  metareplace(1M),  metaroot(1M),  metaset(1M),  metassist(1M),  metastat(1M),	metattach(1M),	md.tab(4),
       md.cf(4), mddb.cf(4), md.tab(4), attributes(5), md(7D)

NOTES

       The metasync service is managed by the service management facility, smf(5), under the service identifier:

	 svc:/system/mdmonitor

       Administrative  actions	on  this  service, such as enabling, disabling, or requesting restart, can be performed using svcadm(1M). The ser-
       vice's status can be queried using the svcs(1) command.

SunOS 5.11							    27 Mar 2006 						      metasync(1M)