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Path: euryale.cc.adfa.oz.au!newshost.anu.edu.au!harbinger.cc.monash.edu.au!news.uwa.edu.au!disco.iinet.net.au!news.uoregon.edu!arclight.uoregon.edu!usenet.eel.ufl.edu!news-feed-1.peachnet.edu!paperboy.wellfleet.com!news3.near.net!sol.caps.maine.edu!web.ddp.state.me.us!gatekeeper.ddp.state.me.us!isdmill From: isdmill@gatekeeper.ddp.state.me.us (David Miller) Newsgroups: comp.unix.bsd.bsdi.misc Subject: Re: Can BSDI 2.0 handle 9GB SCSI Drives? Date: 8 May 1996 16:27:28 GMT Organization: Maine State Government Lines: 53 Message-ID: <4mqi1g$964@web.ddp.state.me.us> References: <4mevk2$a2o@news.hal-pc.org> <4mmkdg$jsb@strange.dfwmm.net> <Dr0vu0.3pC@ritz.mordor.com> NNTP-Posting-Host: gatekeeper.ddp.state.me.us X-Newsreader: TIN [version 1.2 PL2] Chris Mauritz (ritz@ritz.mordor.com) wrote: : I think the ccd driver is a FreeBSD/NetBSD thing, not BSD/OS. It is : apparently in pre-alpha testing now, though I'm told it is working : very well. From the latest README: It is included with 2.1 as "unsupported software" : (3) What it does : In case you don't know what it is, ccd is a disk array driver. You : can combine several disk partitions into one "virtual disk". Then you : can partition it or use the whole thing or add some pepper and salt or : whatever you want. : (4) What it does not : There is no parity support yet. That's why its name doesn't resemble : RAID in any form. However, there is mirroring available starting : from the Jan/31 version. : (4a) Cool, how do I use mirroring? : Add CCDF_MIRROR to the list of flags (third field in /etc/ccd.conf), : and your disk space will magically shrink into half. The writes go to : all disks, while the reads will all come from the first n/2 disks. : If one of the disk goes "poof", you can reconfigure the ccd to use : only half the disks without mirroring. That should keep your users : happy until you get the chance to put in the replacement disk. When : the new disk is installed, use the ccd recovery program called `dd' : (which mysteriously made its way into the release even before we put : out an alpha version of ccd), e.g., to copy sd1g to sd4g, : dd if=/dev/sd1g of=/dev/sd4g bs=1048576 Amazing:) (please note the above recovery utility will only work while sd1g is static) Just to clarify, will the CCD driver do both striping *and* mirroring at the same time? IE mirror a striped set on another striped set? Second, will the driver read from both drives in a mirrored set thereby increasing the reads/sec for the data? Thanks:) -- David Miller Usual disclaimers apply