RAID0 and linear mode are there just for the sake of being there, they can be talked of as the basic state of RAID.
-----Original Message----- From: [EMAIL PROTECTED] [mailto:[EMAIL PROTECTED] On Behalf Of Yashpal Nagar Sent: Saturday, June 21, 2003 11:09 AM To: The Linux-Delhi mailing list Subject: Re: [ilugd] RAID 1/Mirroring on linux On Fri, 2003-06-20 at 21:48, Mithun Bhattacharya wrote: > > --- "Jasmeet S. Virdi" <[EMAIL PROTECTED]> wrote: > > Hi all, > > Hope to get some antennas twitching this time .. I think someone > > talked about RAID 1 on the list sometime back. I want to understand > > the best practices and how to go about doing it. Ne pointers ... > > Linear : no redundancy - preferred where data redundancy is not > required and multiple physical disks need to me merged to create a > single large partition. RAID0 : no redundancy - preferred where data > redundancy data is split into small chunks and spread uniformly over > the complete device - possible use might be a replicated database > since throughput is maximum in this. If no redundancy is there, then what data redundacy you talking about in RAID0. > RAID1 : Data on one disk is mirrored completely onto another. Requires > equal sized disks or the device will provide disk space equal to the > smaller of the two disks. Fast throughput with redundancy - can > survive one disk failure. Highest throughput of all redundancy enabled > RAID system. RAID4 : Parity for n-1 disks is calculated and stored on > the remaining disk Most optimum usage of disk space but also the > slowest of all the RAID systems. Equal sized disks required as in > RAID1. RAID5 : Parity calculated as in RAID4 but data is striped > across the device. Optimum usage of disk space speed enhanced > appreciably due to striping. Recommended where many small sized disks > are available and throughput is important but not of highest > importance. Equal sized disks required. > > In a production environment hardware RAID cards are preferred since it > removes a layer of overhead from the kernel. Database servers are > preferably not kept on RAID devices or if needed then on RAID0. RAID5 > is best kept for internal servers. If less that 3 disks are being used > to create a RAID device go for RAID1 since parity calculation has a > overhead of its own. /boot can be on a software Linear or a RAID1 > device. For all other software RAID devices /boot needs to exist on a > non software RAID device. > > As for how to go about doing it RedHat allows you to setup RAID1 and > RAID5 during installation. For other complex scenarios the Software > RAID HOWTO is best read end to end :). > > > Mithun > regards, -Yash > __________________________________ > Do you Yahoo!? > SBC Yahoo! DSL - Now only $29.95 per month! http://sbc.yahoo.com > > _______________________________________________ > ilugd mailing list > [EMAIL PROTECTED] > http://frodo.hserus.net/mailman/listinfo/ilugd > _______________________________________________ ilugd mailing list [EMAIL PROTECTED] http://frodo.hserus.net/mailman/listinfo/ilugd _______________________________________________ ilugd mailing list [EMAIL PROTECTED] http://frodo.hserus.net/mailman/listinfo/ilugd
