Conor,List 1) Mirrored Redo Logs WRITES may have an Overhead of 15-20 % EXCERPT from Gaja's Doc "One of the common myths with mirroring, is that it takes "twice as long" to write.But in many performance measurements and benchmarks, the overhead has been observed to be around 15-20%."
2) Mirrored Redo Logs READS are Twice as Fast than NON-Mirrored Considering BOTH the Above to POINTS , FINALLY Strictly w.r.t. performance of Online Redo Logs , WITHOUT any Consideration for Data Safety , Which would be Better ? Thanks > -----Original Message----- > From: Connor McDonald [SMTP:[EMAIL PROTECTED]] > Sent: Thursday, November 15, 2001 3:15 PM > To: Multiple recipients of list ORACLE-L > Subject: Re: Configuring for Online Redo Logfiles > > An unmirrored disk will run faster (with respect to > writes) than a mirrored one (not twice as fast since > writes on a mirror are typically done in parallel). > Then again - now you've got an unmirrored redo > log...not a good idea. To get around this, you'd need > to duplex it through Oracle - which pretty much gets > you back to a "mirrored" redo log. > > hth > connor > > --- VIVEK_SHARMA <[EMAIL PROTECTED]> wrote: > > EXCERPT from "Implementing Raid On Oracle Systems" > > by Gaja Krishna > > Vaidyanatha, Quest Software Inc. :- > > "RAID 1 - Ideal for online and archived redo logs, > > Leaves the write-head > > at the location of the last write. On most systems, > > you will need 3 > > volumes for the online redo logs (for 3 groups) and > > 1 volume for the > > archived redo logs. If your database is in > > NOARCHIVELOG mode, you > > probably can get away with a single RAID 1 volume > > for your redo-logs. > > However, for databases in ARCHIVELOG mode you will > > need to further > > separate you" > > Qs. Puttting an Online Redo log on a RAID1 Volume ( > > Volume Containing 1 > > Disk Mirrored to Another Disk ) versus putting the > > Same Online redo file > > on a Single Disk (NON-Mirrored) , which would give > > Better performance , > > Why ? > > -- > > Please see the official ORACLE-L FAQ: > > http://www.orafaq.com > > -- > > Author: VIVEK_SHARMA > > INET: [EMAIL PROTECTED] > > > > Fat City Network Services -- (858) 538-5051 FAX: > > (858) 538-5051 > > San Diego, California -- Public Internet > > access / Mailing Lists > > > -------------------------------------------------------------------- > > To REMOVE yourself from this mailing list, send an > > E-Mail message > > to: [EMAIL PROTECTED] (note EXACT spelling of > > 'ListGuru') and in > > the message BODY, include a line containing: UNSUB > > ORACLE-L > > (or the name of mailing list you want to be removed > > from). You may > > also send the HELP command for other information > > (like subscribing). > > ===== > Connor McDonald > http://www.oracledba.co.uk (mirrored at > http://www.oradba.freeserve.co.uk) > > "Some days you're the pigeon, some days you're the statue" > > __________________________________________________ > Do You Yahoo!? > Everything you'll ever need on one web page from News and Sport to > Email and Music Charts > http://uk.my.yahoo.com > -- > Please see the official ORACLE-L FAQ: http://www.orafaq.com > -- > Author: =?iso-8859-1?q?Connor=20McDonald?= > INET: [EMAIL PROTECTED] > > Fat City Network Services -- (858) 538-5051 FAX: (858) 538-5051 > San Diego, California -- Public Internet access / Mailing Lists > -------------------------------------------------------------------- > To REMOVE yourself from this mailing list, send an E-Mail message > to: [EMAIL PROTECTED] (note EXACT spelling of 'ListGuru') and in > the message BODY, include a line containing: UNSUB ORACLE-L > (or the name of mailing list you want to be removed from). You may > also send the HELP command for other information (like subscribing). -- Please see the official ORACLE-L FAQ: http://www.orafaq.com -- Author: VIVEK_SHARMA INET: [EMAIL PROTECTED] Fat City Network Services -- (858) 538-5051 FAX: (858) 538-5051 San Diego, California -- Public Internet access / Mailing Lists -------------------------------------------------------------------- To REMOVE yourself from this mailing list, send an E-Mail message to: [EMAIL PROTECTED] (note EXACT spelling of 'ListGuru') and in the message BODY, include a line containing: UNSUB ORACLE-L (or the name of mailing list you want to be removed from). You may also send the HELP command for other information (like subscribing).
