RE: SAME, WAFL and RAID

From: Mohan, Ross <MohanR_at_STARS-SMI.com>
Date: Tue, 15 Jan 2002 14:58:08 -0800
Message-ID: <F001.003F0B55.20020115144032@fatcity.com>

SAME =
'stripe and mirror everthing'
BHT =
'butylated hydroxytoluene'

-----Original Message-----From: Deshpande, Kirti [mailto:kirti.deshpande_at_verizon.com]Sent: Tuesday, January 15, 2002 5:29 PMTo: Multiple recipients of list ORACLE-LSubject: RE: SAME, WAFL and RAID
<SPAN

 class=290522822-15012002>Great ! Thanks for the info..
<SPAN

 class=290522822-15012002>
 -
 Kirti
<SPAN

 class=290522822-15012002>
-----Original Message-----From: Nick Wagner [mailto:Nick.Wagner_at_quest.com]Sent: Tuesday, January 15, 2002 3:49 PMTo: Multiple recipients of list ORACLE-LSubject: RE: SAME, WAFL and RAID
 good question... RAID and WALF -- see below. SAME... no idea...
 RAID - (from <A target=_blank
 href="http://www.uni-mainz.de/~neuffer/scsi/what_is_raid.html">http://www.uni-mainz.de/~neuffer/scsi/what_is_raid.html ) What does RAID stand for ? In 1987, Patterson, Gibson and Katz at the University of California Berkeley, published a paper entitled "A Case for Redundant Arrays of Inexpensive Disks (RAID)" . This paper described various types of disk arrays, referred to by the acronym RAID. The basic idea of RAID was to combine multiple small, inexpensive disk drives into an array of disk drives which yields performance exceeding that of a Single Large Expensive Drive (SLED). Additionally, this array of drives appears to the computer as a single logical storage unit or drive.
 The Mean Time Between Failure (MTBF) of the array will be equal to the MTBF of an individual drive, divided by the number of drives in the array. Because of this, the MTBF of an array of drives would be too low for many application requirements. However, disk arrays can be made fault-tolerant by redundantly storing information in various ways. Five types of array architectures, RAID-1 through RAID-5, were defined by the Berkeley paper, each providing disk fault-tolerance and each offering different trade-offs in features and performance. In addition to these five redundant array architectures, it has become popular to refer to a non-redundant array of disk drives as a RAID-0 array. WAFL (from the NetApp website) The
 WAFL (Write Anywhere File Layout) file system and the following features deliver enterprise-class availability: Consistency
 points. Always a consistent file-system image on disk, even after unplanned shutdowns. Virtually eliminates the need to run time-consuming file-system checks.
 Snapshot
 technology. Snapshots are near-instantaneous, transparent, read-only, online copies of the active file systems. Up to 31 Snapshots can be maintained for each data volume. Users can quickly recover deleted or modified files without administrative assistance or restore from tape backup. The Snapshot function requires minimal disk space and causes no disruption of service. Snapshots can be backed up to other media while users are modifying the active file system to minimize business disruption.
 SnapRestore
 software. Allows any system to revert back to a specified data volume Snapshot for instant file-system recovery. Terabytes can be recovered in minutes, rather than hours, without going to tape. The software also greatly facilitates scenario testing as well as providing disaster recovery and virus protection.
 Easy, cost-effective clustering. Safeguards against hardware failures by automatic filer takeover. Gives users continuous access to data.

SnapMirror software. Provides remote mirroring at high speeds over a LAN or WAN. The asynchronous mirroring can be used for disaster recovery, replication, backup, or testing on a nonproduction system.

-----Original Message----- From:
 Deshpande, Kirti [<A
 href="mailto:kirti.deshpande_at_verizon.com">mailto:kirti.deshpande_at_verizon.com] Sent: Tuesday, January 15, 2002 1:23 PM To: Multiple recipients of list ORACLE-L Subject: RE: SAME, WAFL and RAID Good idea..
 All I know about WAFL is the House where breakfast is served ;)

Kirti -----Original Message----- Sent: Tuesday, January 15, 2002 2:57 PM To: Multiple recipients of list ORACLE-L May I make a suggestion? It would be helpful if posters would expand acronyms the first time they use them. I, at least, have no idea what WAFL is. Thanks.
- Bill Becker <beckerb_at_mfldclin.edu> wrote: > Hello, > > I am looking for any pointers to white papers, etc. > that discuss the differences/similarities among > WAFL, SAME and RAID
 Do You Yahoo!? Send FREE video emails in Yahoo! Mail! <A target=_blank href="http://promo.yahoo.com/videomail/">http://promo.yahoo.com/videomail/
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Received on Tue Jan 15 2002 - 16:58:08 CST