Creating a RAID5 Volume

A RAID5 volume uses storage capacity equivalent to one slice in the volume to store redundant information about user data stored on the remainder of the RAID5 volume's slices. The redundant information is distributed across all slices in the volume. Like a mirror, a RAID5 volume increases data availability, but with a minimum of cost in terms of hardware.

The system must contain at least three state database replicas before you can create RAID5 volumes.

A RAID5 volume can only handle a single slice failure.

Follow the 20-percent rule when creating a RAID5 volume: because of the complexity of parity calculations, volumes with greater than about 20 percent writes should probably not be RAID5 volumes. If data redundancy is needed, consider mirroring.

There are drawbacks to a slice-heavy RAID5 volume: the more slices a RAID5 volume contains, the longer read and write operations will take if a slice fails.

A RAID5 volume must consist of at least three slices. A RAID5 volume can be grown by concatenating additional slices to the volume. The new slices do not store parity information, however they are parity protected. The resulting RAID5 volume continues to handle a single slice failure.

The interlace value is key to RAID5 performance. It is configurable at the time the volume is created; thereafter, the value cannot be modified. The default interlace value is 16 Kbytes. This is reasonable for most applications.

Use the same size disk slices. Creating a RAID5 volume from different size slices results in unused disk space in the volume.

Do not create a RAID5 volume from a slice that contains an existing file system. Doing so will erase the data during the RAID5 initialization process.

RAID5 volumes cannot be striped, concatenated, or mirrored.

  1. The following example creates a RAID 5 volume using 3 slices that will be named /dev/md/rdsk/d3 with the metainit command. Of the twelve disks available in the D1000 Disk Array, I will be using slices c1t4d0s7, c2t4d0s7, and c1t5d0s7 as follows:
    # metainit d3 -r c1t4d0s7 c2t4d0s7 c1t5d0s7
    d3: RAID is setup

    Let's explain the details of the above example. The RAID5 volume d3 is created with the -r option from three slices. Because no interlace is specified, d3 uses the default of 16 Kbytes. The system verifies that the RAID5 volume has been set up, and begins initializing the volume.


  2. Use the metastat command to query your new RAID5 volumes. After running the above command, the volume will go through an initialization state. This may take several minutes to complete. When using the metastat command, you will be able to view how far of the initialization is completed. You must wait for the initialization to finish before you can use the new RAID5 volume. The following screenshot shows the RAID5 volume during its initialization phase:
    # metastat d3
    d3: RAID
        State: Initializing
        Initialization in progress: 32.0% done
        Interlace: 32 blocks
        Size: 35331849 blocks (16 GB)
    Original device:
        Size: 35334720 blocks (16 GB)
            Device     Start Block  Dbase        State Reloc  Hot Spare
            c1t4d0s7      11103       Yes Initializing   Yes
            c2t4d0s7      11103       Yes Initializing   Yes
            c1t5d0s7      11103       Yes Initializing   Yes
    Device Relocation Information:
    Device   Reloc  Device ID
    c1t4d0   Yes    id1,sd@SSEAGATE_ST39102LCSUN9.0GLJP248260000194511NU
    c2t4d0   Yes    id1,sd@SSEAGATE_ST39102LCSUN9.0GLJP1841500002945H5FE
    c1t5d0   Yes    id1,sd@SSEAGATE_ST39102LCSUN9.0GLJE34597000029290C8N

    When the disks within the RAID5 volume are completed with their initialization phase, this is what it will look like:

    # metastat d3
    d3: RAID
        State: Okay
        Interlace: 32 blocks
        Size: 35331849 blocks (16 GB)
    Original device:
        Size: 35334720 blocks (16 GB)
            Device     Start Block  Dbase        State Reloc  Hot Spare
            c1t4d0s7      11103       Yes         Okay   Yes
            c2t4d0s7      11103       Yes         Okay   Yes
            c1t5d0s7      11103       Yes         Okay   Yes
    Device Relocation Information:
    Device   Reloc  Device ID
    c1t4d0   Yes    id1,sd@SSEAGATE_ST39102LCSUN9.0GLJP248260000194511NU
    c2t4d0   Yes    id1,sd@SSEAGATE_ST39102LCSUN9.0GLJP1841500002945H5FE
    c1t5d0   Yes    id1,sd@SSEAGATE_ST39102LCSUN9.0GLJE34597000029290C8N


  3. Now that we have created our RAID5 volume, we can now pretend that the volume is a big partition (slice) on which we can do the usual file system things. Let's now create a UFS file system using the newfs command. I want to create a UFS file system with an 8KB block size:
    # newfs -i 8192 /dev/md/rdsk/d3
    newfs: construct a new file system /dev/md/rdsk/d3: (y/n)? y
    Warning: 1 sector(s) in last cylinder unallocated
    /dev/md/rdsk/d3:        35331848 sectors in 9839 cylinders of 27 tracks, 133 sectors
            17251.9MB in 615 cyl groups (16 c/g, 28.05MB/g, 3392 i/g)
    super-block backups (for fsck -F ufs -o b=#) at:
     32, 57632, 115232, 172832, 230432, 288032, 345632, 403232, 460832, 518432,
    Initializing cylinder groups:
    super-block backups for last 10 cylinder groups at:
     34765088, 34822688, 34880288, 34933280, 34990880, 35048480, 35106080,
     35163680, 35221280, 35278880,


  4. Finally, we mount the file system on /db3 as follows:
    # mkdir /db3
    # mount -F ufs /dev/md/dsk/d3 /db3


  5. To ensure that this new file system is mounted each time the machine is started, insert the following line into you /etc/vfstab file (all on one line with tabs separating the fields):
    /dev/md/dsk/d3       /dev/md/rdsk/d3      /db3  ufs     2       yes     -

Recommended Links

Creating Volumes - (Using Solaris 9 Volume Manager Commands)



Groupthink : Two Party System as Polyarchy : Corruption of Regulators : Bureaucracies : Understanding Micromanagers and Control Freaks : Toxic Managers :   Harvard Mafia : Diplomatic Communication : Surviving a Bad Performance Review : Insufficient Retirement Funds as Immanent Problem of Neoliberal Regime : PseudoScience : Who Rules America : Neoliberalism  : The Iron Law of Oligarchy : Libertarian Philosophy


War and Peace : Skeptical Finance : John Kenneth Galbraith :Talleyrand : Oscar Wilde : Otto Von Bismarck : Keynes : George Carlin : Skeptics : Propaganda  : SE quotes : Language Design and Programming Quotes : Random IT-related quotesSomerset Maugham : Marcus Aurelius : Kurt Vonnegut : Eric Hoffer : Winston Churchill : Napoleon Bonaparte : Ambrose BierceBernard Shaw : Mark Twain Quotes


Vol 25, No.12 (December, 2013) Rational Fools vs. Efficient Crooks The efficient markets hypothesis : Political Skeptic Bulletin, 2013 : Unemployment Bulletin, 2010 :  Vol 23, No.10 (October, 2011) An observation about corporate security departments : Slightly Skeptical Euromaydan Chronicles, June 2014 : Greenspan legacy bulletin, 2008 : Vol 25, No.10 (October, 2013) Cryptolocker Trojan (Win32/Crilock.A) : Vol 25, No.08 (August, 2013) Cloud providers as intelligence collection hubs : Financial Humor Bulletin, 2010 : Inequality Bulletin, 2009 : Financial Humor Bulletin, 2008 : Copyleft Problems Bulletin, 2004 : Financial Humor Bulletin, 2011 : Energy Bulletin, 2010 : Malware Protection Bulletin, 2010 : Vol 26, No.1 (January, 2013) Object-Oriented Cult : Political Skeptic Bulletin, 2011 : Vol 23, No.11 (November, 2011) Softpanorama classification of sysadmin horror stories : Vol 25, No.05 (May, 2013) Corporate bullshit as a communication method  : Vol 25, No.06 (June, 2013) A Note on the Relationship of Brooks Law and Conway Law


Fifty glorious years (1950-2000): the triumph of the US computer engineering : Donald Knuth : TAoCP and its Influence of Computer Science : Richard Stallman : Linus Torvalds  : Larry Wall  : John K. Ousterhout : CTSS : Multix OS Unix History : Unix shell history : VI editor : History of pipes concept : Solaris : MS DOSProgramming Languages History : PL/1 : Simula 67 : C : History of GCC developmentScripting Languages : Perl history   : OS History : Mail : DNS : SSH : CPU Instruction Sets : SPARC systems 1987-2006 : Norton Commander : Norton Utilities : Norton Ghost : Frontpage history : Malware Defense History : GNU Screen : OSS early history

Classic books:

The Peter Principle : Parkinson Law : 1984 : The Mythical Man-MonthHow to Solve It by George Polya : The Art of Computer Programming : The Elements of Programming Style : The Unix Haterís Handbook : The Jargon file : The True Believer : Programming Pearls : The Good Soldier Svejk : The Power Elite

Most popular humor pages:

Manifest of the Softpanorama IT Slacker Society : Ten Commandments of the IT Slackers Society : Computer Humor Collection : BSD Logo Story : The Cuckoo's Egg : IT Slang : C++ Humor : ARE YOU A BBS ADDICT? : The Perl Purity Test : Object oriented programmers of all nations : Financial Humor : Financial Humor Bulletin, 2008 : Financial Humor Bulletin, 2010 : The Most Comprehensive Collection of Editor-related Humor : Programming Language Humor : Goldman Sachs related humor : Greenspan humor : C Humor : Scripting Humor : Real Programmers Humor : Web Humor : GPL-related Humor : OFM Humor : Politically Incorrect Humor : IDS Humor : "Linux Sucks" Humor : Russian Musical Humor : Best Russian Programmer Humor : Microsoft plans to buy Catholic Church : Richard Stallman Related Humor : Admin Humor : Perl-related Humor : Linus Torvalds Related humor : PseudoScience Related Humor : Networking Humor : Shell Humor : Financial Humor Bulletin, 2011 : Financial Humor Bulletin, 2012 : Financial Humor Bulletin, 2013 : Java Humor : Software Engineering Humor : Sun Solaris Related Humor : Education Humor : IBM Humor : Assembler-related Humor : VIM Humor : Computer Viruses Humor : Bright tomorrow is rescheduled to a day after tomorrow : Classic Computer Humor

The Last but not Least Technology is dominated by two types of people: those who understand what they do not manage and those who manage what they do not understand ~Archibald Putt. Ph.D

Copyright © 1996-2020 by Softpanorama Society. was initially created as a service to the (now defunct) UN Sustainable Development Networking Programme (SDNP) without any remuneration. This document is an industrial compilation designed and created exclusively for educational use and is distributed under the Softpanorama Content License. Original materials copyright belong to respective owners. Quotes are made for educational purposes only in compliance with the fair use doctrine.

FAIR USE NOTICE This site contains copyrighted material the use of which has not always been specifically authorized by the copyright owner. We are making such material available to advance understanding of computer science, IT technology, economic, scientific, and social issues. We believe this constitutes a 'fair use' of any such copyrighted material as provided by section 107 of the US Copyright Law according to which such material can be distributed without profit exclusively for research and educational purposes.

This is a Spartan WHYFF (We Help You For Free) site written by people for whom English is not a native language. Grammar and spelling errors should be expected. The site contain some broken links as it develops like a living tree...

You can use PayPal to to buy a cup of coffee for authors of this site


The statements, views and opinions presented on this web page are those of the author (or referenced source) and are not endorsed by, nor do they necessarily reflect, the opinions of the Softpanorama society. We do not warrant the correctness of the information provided or its fitness for any purpose. The site uses AdSense so you need to be aware of Google privacy policy. You you do not want to be tracked by Google please disable Javascript for this site. This site is perfectly usable without Javascript.

Last modified: March 12, 2019