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

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:

       -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 128 512-byte disk blocks (64 Kbytes). It can be no more than 2048 blocks. For best performance (quick-
			       est 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)

       Solaris Volume Manager Administration Guide

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 5.10							    24 Nov 2004 						      metasync(1M)