Re: Database and RAID

In article <01bd9a5d$d7ce4ee0$30647392@default>, Doug Johnson <teabag@ma .deleteme.ultranet.com> writes >The correct sequence is sync h/w mirror, CKPT&BLOCK, split mirror, then >UNBLOCK. >The split takes seconds for GB databases, maybe a couple of minutes for TB >databases. Since the CKPT blocks writers, the new BLOCK for split extends >the writer-freeze but as always readers continue and no clients are >dropped. > PS How do you freeze Online??? onlog ... | more and pause it. It holds a latch... Next CKPINTVL is reached an the checkpoint can't proceed because of the latch and nothing can proceed (enter critical sections) because the checkpoint is in progress. Nasty.... >..snip useful clarification >> Set the mode to BLOCK, turn on your h/w mirror, when it is sync'ed turn >> it back off and UNBLOCK your system. >> Dave >> >> Dave Kosenko davek@summitdata.com >> Director of Training Services (732) 469-4070 >> Summit Data Group (an Informix Authorized Education Center) >> -- David Williams Maintainer of the Informix FAQ Primary site (Beta Version) http://www.smooth1.demon.co.uk Official site http://www.iiug.org/techinfo/faq/faq_top.html I see you standin', Standin' on your own, It's such a lonely place for you, For you to be If you need a shoulder, Or if you need a friend, I'll be here standing, Until the bitter end... So don't chastise me Or think I, I mean you harm... All I ever wanted Was for you To know that I care