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Windows Server 8 to Get a New File System: ReFS

By - Source: Microsoft | B 46 comments

Microsoft will be introducing a new file system with Windows 8 Server, called ReFS, which is built on top of the existing NTFS, but will deliver new features for scale and prevent data corruption.

ReFS, short for Resilient File System, will initially debut with Windows 8 Server, but is expected to make its way through to Windows 8 client system to support the full feature set of Storage Spaces, which will allow users to create storage pools from multiple physical and virtual storage devices.

According to Microsoft, ReFS will be an always-online file system "for the next decade or more" that is architected for "extreme scale" with large volume, file and directory sizes, as well as data verification and auto-correction via checksums while maintaining compatibility with a "wide subset of widely adopted" NTFS features.

ReFS will support a maximum size of 4 PB per storage pool path and file lengths of up to 32,000 (unicode) characters, up to 2^64 (18,446,744,100,000,000,000 or about 18 quintillion) directories in a storage volume, and up to 2^64 files in a single directory. ReFS also supports, in theory, to a maximum volume size of 2^78 bytes, as Windows stack addressing is limited to 2^64 bytes, which translates to 16,384 PB. The file size limit is 2^64-1 bytes.

REFS's most critical feature, however, may be its ability to answer data corruption on-the-fly, as all ReFS metadata is check-summed across multiple volumes (in storage spaces environments), which enables the technology to detect disk corruptions. If the user chooses to activate file checksums (integrity streams) as well, ReFS will always give preference to the original file over the newer file. "This allocate-on-write technique ensures that pre-existing data is not lost due to the new write," wrote Surendra Verma, a development manager on Microsoft's Storage and File System team. "The checksum update is done atomically with the data write, so that if power is lost during the write, we always have a consistently verifiable version of the file available whereby corruptions can be detected authoritatively."

Just like NTFS, Microsoft will be testing and deploying ReFS in server environments initially. However, its feature may have true advantages in combined server-client environment, especially if we include cloud-computing services and storage pools. Expect ReFS to become available on your desktop and notebook PC in the foreseeable future as Verma noted that ReFS will be "the next massively deployed file system."

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  • 17 Hide
    Marco925 , January 21, 2012 9:38 PM
    jprahmanI heard about this 4 days ago. Yawn.

    Then dont click on it. you had a choice sir...
  • 15 Hide
    A Bad Day , January 21, 2012 7:40 PM
    I don't understand the graphs of NTFS and ReFS. Can anyone explain?
  • 12 Hide
    jcaulley_74 , January 21, 2012 5:04 PM
    nforce4maxDoes it support files with names greater than 256 characters long? I often have to rename files (web pages) that I download because their names being outrageously long that some are up to 384 characters long.


    freggoUh, am I missing something or is this a typo.What is a 'file length' ?Do they mean file NAME or Sector size ?


    "path and file (name) lengths of up to 32,000 (unicode) characters"
Other Comments
  • -3 Hide
    hannibal , January 21, 2012 4:48 PM
    Yep. Interesting to see if we see full implementation of this in win8 servicepack or in win9.
    In anyway nice upgrade, that will have greater impact later, when it is properly tested and allowed to use allso in boot sector.
  • -4 Hide
    freggo , January 21, 2012 5:00 PM
    "file lengths of up to 32,000 (unicode) characters"

    Uh, am I missing something or is this a typo.
    What is a 'file length' ?
    Do they mean file NAME or Sector size ?
  • 12 Hide
    jcaulley_74 , January 21, 2012 5:04 PM
    nforce4maxDoes it support files with names greater than 256 characters long? I often have to rename files (web pages) that I download because their names being outrageously long that some are up to 384 characters long.


    freggoUh, am I missing something or is this a typo.What is a 'file length' ?Do they mean file NAME or Sector size ?


    "path and file (name) lengths of up to 32,000 (unicode) characters"
  • 10 Hide
    jcaulley_74 , January 21, 2012 5:11 PM
    Other relevant info from the ReFS blog:

    "Q) Can I boot from ReFS in Windows Server 8?

    No, this is not implemented or supported.

    Q) Can ReFS be used on removable media or drives?

    No, this is not implemented or supported.

    Q) What semantics or features of NTFS are no longer supported on ReFS?

    The NTFS features we have chosen to not support in ReFS are: named streams, object IDs, short names, compression, file level encryption (EFS), user data transactions, sparse, hard-links, extended attributes, and quotas."
  • 2 Hide
    jimmysmitty , January 21, 2012 5:26 PM
    jcaulley_74Other relevant info from the ReFS blog:"Q) Can I boot from ReFS in Windows Server 8?No, this is not implemented or supported.Q) Can ReFS be used on removable media or drives?No, this is not implemented or supported.Q) What semantics or features of NTFS are no longer supported on ReFS?The NTFS features we have chosen to not support in ReFS are: named streams, object IDs, short names, compression, file level encryption (EFS), user data transactions, sparse, hard-links, extended attributes, and quotas."


    As with any new file system, it takes time to become adopted. NTFS was not fully adopted until late into XPs release, some people were still using FAT32.

    Honestly though it looks interesting. Looks more geared towards servers, as NTFS does what we need for DT but maybe it will incorporate a few things from the now dead WINFS.....
  • -4 Hide
    alxianthelast , January 21, 2012 5:39 PM
    What 'were' some people maddeningly remain on Xp FAT32.
  • -7 Hide
    warezme , January 21, 2012 5:50 PM
    Just curious, how is this done "atomically" , "The checksum update is done atomically..."? Will we be using quantum computing with windows 8?
  • -1 Hide
    ojas , January 21, 2012 6:18 PM
    Looking at the changes they're making going from win 7 to 8...I'm getting a very strong feeling that Win 9 will turn out to be a master of all trades...great for power users, great for gamers, great for consumption devices and great for servers/enterprises...I mean, they'll have some teething troubles with Win 8 as they did with Vista, but they'll refine it in the end.

    Win 9 will hopefully spur Apple into make a better OS too...but i know they'll be happy with a blown up version of a mobile OS so hopefully Mac OS goes extinct...long live Winux! (or Lindows :p  )
  • -8 Hide
    Anonymous , January 21, 2012 6:23 PM
    I will be using FAT32 until Western Digital stops making formating options for it ! Or I buy disks with this parallel recording system.......
  • 1 Hide
    danwat1234 , January 21, 2012 7:08 PM
    nforce4maxDoes it support files with names greater than 256 characters long? I often have to rename files (web pages) that I download because their names being outrageously long that some are up to 384 characters long. Web masters should consider article numbers or a web page naming scheme that isn't a directory or a long title and directory -_- I wonder how much better win serv 8 is compared to 2003 and 2008 R2.


    I don't know about file NAME lengths larger than 256 characters, but file PATHS longer than 255 or 256 characters is very annoying in windows 7 because Explorer throws a fit when the path is this long. So, I use Total Commander. I hope Win8 (with regular NTFS) supports longer path lengths!
  • 15 Hide
    A Bad Day , January 21, 2012 7:40 PM
    I don't understand the graphs of NTFS and ReFS. Can anyone explain?
  • 17 Hide
    Marco925 , January 21, 2012 9:38 PM
    jprahmanI heard about this 4 days ago. Yawn.

    Then dont click on it. you had a choice sir...
  • 0 Hide
    madooo12 , January 21, 2012 10:08 PM
    freggo"file lengths of up to 32,000 (unicode) characters"Uh, am I missing something or is this a typo.What is a 'file length' ?Do they mean file NAME or Sector size ?

    i think they mean the whole length like C:\windows\system32\123.sys
    or maybe filename who knows
  • -5 Hide
    alidan , January 21, 2012 11:16 PM
    if it wanst a file system and just a feature, i would get win8 in a heartbeat for 32k character limit, constantly have to rename crap as it stands because of long names.
  • -1 Hide
    shin0bi272 , January 22, 2012 12:03 AM
    freggo"file lengths of up to 32,000 (unicode) characters"Uh, am I missing something or is this a typo.What is a 'file length' ?Do they mean file NAME or Sector size ?

    "c:\someHugeDirectory\someHugeDirectory\myFolder\myFile.mp3" That's the path.
    Currently windows only supports 256 characters from c: through .mp3...

    Ive run into issue with this at work when people want their file named "customer's lastname, customers first name, customers DOB, visit type.pdf" If I were to try to export that to a server from my local pc it would have to be something like "z:\someHugeDirectory\someHugeDirectory\someHugeDirectory\someHugeDirectory\finalDirectory\customer's lastname, customers first name, customers DOB, visit type.pdf" So as you can see it runs out of characters fast and my file name ends up being truncated or the program wont export it at all. This will stop that
  • -1 Hide
    freggo , January 22, 2012 12:38 AM
    shin0bi272"c:\someHugeDirectory\someHugeDirectory\myFolder\myFile.mp3" That's the path. Currently windows only supports 256 characters from c: through .mp3... Ive run into issue with this at work when people want their file named "customer's lastname, customers first name, customers DOB, visit type.pdf" If I were to try to export that to a server from my local pc it would have to be something like "z:\someHugeDirectory\someHugeDirectory\someHugeDirectory\someHugeDirectory\finalDirectory\customer's lastname, customers first name, customers DOB, visit type.pdf" So as you can see it runs out of characters fast and my file name ends up being truncated or the program wont export it at all. This will stop that



    Yes, I figured something along the filename/path thing.
    Also I rarely use long filenames myself. Programming background... lazy, we hate to type long variables :-)

    and before someone yells CUT and PASTE... I am the generation well before cut and paste. I speak peek and poke and old habits die hard :-)
  • -3 Hide
    ajay_vishvanathan , January 22, 2012 1:24 AM
    oops.. sorry.. made the wrong post..
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