Best use of 4 disks in RAID


Recommended Posts

What is the best use of 4 disks which gives me most storage but with some form of data redundancy? I was just going to mirror 2 disks to the other 2 but that's obviously not the best use of space. Can striped with parity work with 4 disks? I was always always under the impression its a 3 drive operation (stripes on 2, parity on 1) but would like to be corrected.

Thanks

Link to comment
https://www.neowin.net/forum/topic/1097369-best-use-of-4-disks-in-raid/
Share on other sites

It really depends on what you need out of it. If data integrity is the absolute most important then RAID 1.

If you need integrity and more space than a single drive offers, RAID10. RAID10 will give you the highest level of data redundancy (a complete mirror!) but not as much space as RAID-5. But think about it... one drive fails, and you're without your data for hours to days while it rebuilds (if it completes...)

I don't recommend RAID-5. It's becoming more likely to fail. Raid-6 if you MUST, but don't RAID-5.

http://www.smbitjour...-more-reliable/

http://www.smbitjour...-or-a-hot-mess/

RAID5.jpeg

  On 09/08/2012 at 22:28, Tony. said:

RAID-5 is probably the best option. RAID-0+1 would just half the amount of storage you have available. As for the comment above about RAID-5 reliability, software RAID is risky business anyways.

The first link was for you then ;)

6TB RAID-5, 50% chance of URE. 12TB, 100% chance. 3TB array, 25%.

"6TB RAID-5, 50% chance of URE. 12TB, 100% chance. 3TB array, 25%."

I don't think your doing the math right..

http://www.raidtips.com/raid5-ure.aspx

This scare mongering has been around for many many years.. Raid 5 was suppose to be dead in 2009, its mid 2012.. So something is not quite right.

I agree with you that there are lots of articles saying that raid 5 is dead.. But strangely its not ;)

What I would suggest, is if you have data that your worried about it being offline - which is the whole reason of raid. That you feel you should run raid, I would make SURE you have BACKUP!!! Raid is not a BACKUP!!

Raid with parity is a method of mitigating having to restore from backup, on minor hardware failure (1 disk out of many).

What disks do you have? Not all disks are good choices for raids, and yes a rebuild can put a strain on your other disks as they are hit to rebuild the failed one. So if they are not in good shape, its possible they could fail on a rebuild.

As mentioned in the article I linked too that points out what is being said might be a bit exaggerated lets say. Lets look at this statement from your link

"the rate of URE is 10^14, or once every twelve terabytes of read operations. That means that a six terabyte array being resilvered has a roughly fifty percent chance of hitting a URE and failing."

I don't buy that, for starters sure a URE could be a major problem - but I don't buy his math on the likelyhood of hitting one. For starters who says there is 6TB of data on my 6TB array that needs to be rebuilt? Do you run your ARRAY at 100% Cap?? So your 6TB array has what being used 3TB? Which is stripped over all the disks in the array right. So for 6TB of data your talking 4x2TB (you loose 1 disk for parity in raid 5 right - which is striped across all disks)

So my 3TB of data is striped across 4 disks with the added parity your talking 4TB of written stuff (3TB of data and 1TB of party), or 1TB on each disk. So to restore that data you have to read 1TB off each disk that is left in your 4disk array. The raid magic then happens and using parity recreates the 1TB that is gone off the failed disk.

So if each disk could have a bad sector that could cause a URE - what are the odds that its in the 1TB I am going to read off each disk? I don't think its as simple as they are saying that a URE happens in every 12TB of read data.

What I am trying to say is don't take these Doom Sayers as gospel.. If that was true - raid 5 would of been dead back in 2009 like they were saying ;) Its 2012 and raid 5 is still here. Like they are saying raid 6 will be dead in 2019 ;)

edit: As to the OP question at hand - even though I think raid 5 is still a viable option. I would prob not go that route myself, there are many many different options these days with newer ways to use your diskspace while still providing parity and ability to rebuild data on loss of disk. Unraid comes to mind, snapraid, flexraid. There are also methods of just keeping your critical data on your storage on more than one disk, while not having to create parity for every single bit. Drive extender, DrivePool from stablebit, etc. etc. Im currently using drivepool for my storage needs. It allows me to assign folders in my storage that need to be stored on more than 1 disk, so that if 1 disk fails I don't have to worry about restoring those files from backup.

Because most of my data I would never backup or even worry about restore if lost, but some of it I do backup!! And is critical - so I just keep multiple copies of it on multiple disks in my storage array.

This topic is now closed to further replies.
  • Recently Browsing   0 members

    • No registered users viewing this page.
  • Posts

    • I always disable animations in Windows using sysdm.cpl and yes, it feels faster. I have also reduced animations in my android phone using dev options.
    • Neowin's servers (hosted in the UK).
    • MacOS isn't Linux, but Proton is modified WINE, and WINE runs on MacOS. They would just need to add something like Box86 or Rosetta support.
    • PicPick 7.4.0 by Razvan Serea PicPick is user friendly and full of features for creating your image, suitable for software developers, graphic designers and the home user. It is an all-in-one program that provides a full-featured screen capture tool, intuitive image editor, color picker, color palette, pixel ruler, protractor, crosshair and even whiteboard. It not only has everything that you need, but it loads fast, and sits quietly in the system tray until needed. This software is provided as freeware for personal use only. In this case, you are granted the right to use this program free of charge. Otherwise, you need to pay for a license for commercial use. PicPick key features: For All Windows (Fully support Windows 11, 10, 8.1, 8, 7, Vista and XP both 32-bit and 64-bit) Multi-language is supported. (MORE 28+) All functions are fully supported on a dual screen environment. No Registry, No access to System folder (you can copy these files to portable USB) Screen Capture Auto-scroll, dual monitors and sound effect are supported Various output to File, Printer, Office programs, External program Sharing to FTP, Web, E-mail, Facebook and Twitter are supported as well Full Screen Active Window Window Control Scrolling Window Region, Fixed Region FreeHand Repeat Last Capture Image Editor Intuitive User Interface Windows Ribbon style Standard drawing, shapes, arrows, lines, text, and etc. Blur, sharpen, hue, contrast, brightness, pixelate, rotate, flip, frame effect and etc. Color Picker and Color Palette various color code type (RGB, HTML, C++, Delphi) Photoshop style RGB/HSV conversion is supported. Pick and Save your favorite color! Screen Pixel Ruler Horizontal and vertical orientation various units (Pixels, Inches, Centimeters) DPI setting (72, 96, 120, 300) colorful gradient skins You don't have to install any other screen ruler softwares. Screen Magnifier Zoom 2x to 10x option Stay on top, smooth display, and sizeable window Screen Protractor Have you seen any screen protractor function in other software? Screen Crosshair For aligning objects in graphics or design applications For calculating relative coordinates on screen Some prefer to use this tool than a pixel-ruler. Whiteboard For giving a presentation or just drawing something on screen PicPick 7.4.0 changelog: Added support for saving in WebP file format Added horizontal scrolling in the Image Editor with Shift and mouse wheel Fixed control capture failing to detect specific windows Fixed focus loss during delayed active-window captures. Download: PicPick 7.4.0 | 74.9 MB (Free for personal use only) Download: Portable PicPick 7.4.0 | 73.3 MB View: PicPick Home page | Screenshot Get alerted to all of our Software updates on Twitter at @NeowinSoftware
    • Stellarium 25.2 by Razvan Serea Stellarium is a free open source planetarium for your computer. It shows a realistic sky in 3D, just like what you see with the naked eye, binoculars or a telescope. It is being used in planetarium projectors. Just set your coordinates and go. Stellarium key features: Realistic simulation of the sky, sunrise and sunset Default catalogue of over 600,000 stars Downloadable additional catalogues for up to 210 million stars Catalog data for all New General Catalogue (NGC) objects Images of almost all Messier objects and the Milky Way Artistic illustrations for all 88 modern constellations More than a dozen different cultures with their constellations Solar and lunar eclipse simulation Photorealistic landscapes (more are available on the website) Scripting support with ECMAScript (a few demo scripts are included) Extendable with plug-ins: 8 plug-ins installed by default, including: artificial satellites plug-in (updated from an on-line TLE database) ocular simulation plug-in (shows how objects look like in a given ocular) Solar System editor plug-in (imports comet and asteroid data from the MPC) telescope control plug-in (Meade LX200 and Celestron NexStar compatible) The major changes of this version: Many changes in support of sky cultures Added 2 new plugins: Mosaic Camera and Custom Nebula Textures Many improvements in Core Updates in sky cultures (include new one) [full release notes] Download: Stellarium 25.2 (64-bit) | 361.0 MB (Open Source) View: Stellarium Home Page | Other Operating Systems | Screenshot Get alerted to all of our Software updates on Twitter at @NeowinSoftware
  • Recent Achievements

    • First Post
      Johnny Mrkvička earned a badge
      First Post
    • Week One Done
      viraltui earned a badge
      Week One Done
    • One Month Later
      serfegyed earned a badge
      One Month Later
    • Dedicated
      firey earned a badge
      Dedicated
    • Dedicated
      fettermanj earned a badge
      Dedicated
  • Popular Contributors

    1. 1
      +primortal
      651
    2. 2
      Michael Scrip
      224
    3. 3
      ATLien_0
      222
    4. 4
      Xenon
      146
    5. 5
      +FloatingFatMan
      142
  • Tell a friend

    Love Neowin? Tell a friend!