ReFS replacing NTFS in Windows 8
The ReFS stands for Resilient File System. ReFS will be
introduced as a part of Windows Server 8 operating system. In a blog
post published by Windows 8 team, author
Surendra Verma talks about new features and how it is different than current
file system NTFS. Author also mentioned that this file system is designed from
ground up to meet today's and tomorrow's needs.
When you compare Windows PC and Apple operating system,
first thing I hear is how unreliable Windows is. Apple users talk about how
their system never crashes but I see Windows crashing all the time. I think
Windows 8 team's main focus is these problems. Windows 8 team's focus has been
data integrity, storage structure and so on.
Here is a list of key features of ReFS:
ReFS is rebuilt from ground up with keeping in mind today's
and tomorrow needs.
Written has written smartly. Windows 8 team talks about reusing
the code and kept it compatible. Blog reads, “This code implements the file
system interface (read, write, open, close, change notification, etc.),
maintains in-memory file and volume state, enforces security, and maintains
memory caching and synchronization for file data. This reuse ensures a high
degree of compatibility with the features of NTFS that we're carrying forward”.
I think of this way. The previous system
was written using C++ but the new system is written using C# J
ReFS has reliable and scalable on-disk structure using B+
trees and ACLs.
ReFS has a robust disk update strategy
ReFS is resilient to disk corruptions. No more blue screens.
I wish and data loss. I wish J
ReFS continues to have disk volume available even it fails.
ReFS has a reliable
and scalable on-disk structure. To me, it seems like we will see none or
less blue screens and other file system issues that we are used to seeing J
You can read more details here
Here are some FAQs about ReFS published by Windows 8 team.
Q)
Why is it named ReFS?
ReFS stands for
Resilient File System. Although it is designed to be better in many dimensions,
resiliency stands out as one of its most prominent features.
Q)
What are the capacity limits of ReFS?
The table below
shows the capacity limits of the on-disk format. Other concerns may determine
some practical limits, such as the system configuration (for example, the
amount of memory), limits set by various system components, as well as time
taken to populate data sets, backup times, etc.
|
Attribute
|
Limit
based on the on-disk format
|
|
Maximum
size of a single file
|
2^64-1
bytes
|
|
Maximum
size of a single volume
|
Format
supports 2^78 bytes with 16KB cluster size (2^64 * 16 * 2^10). Windows stack
addressing allows 2^64 bytes
|
|
Maximum
number of files in a directory
|
2^64
|
|
Maximum
number of directories in a volume
|
2^64
|
|
Maximum
file name length
|
32K
unicode characters
|
|
Maximum
path length
|
32K
|
|
Maximum
size of any storage pool
|
4
PB
|
|
Maximum
number of storage pools in a system
|
No
limit
|
|
Maximum
number of spaces in a storage pool
|
No
limit
|
Q) Can I convert data between NTFS and ReFS?
In Windows 8
there is no way to convert data in place. Data can be copied. This was an
intentional design decision given the size of data sets that we see today and
how impractical it would be to do this conversion in place, in addition to the
likely change in architected approach before and after conversion.
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.
Q)
What about parity spaces and ReFS?
ReFS is supported
on the fault resiliency options provided by Storage Spaces. In Windows Server
8, automatic data correction is implemented for mirrored spaces only.
Q)
Is clustering supported?
Failover
clustering is supported, whereby individual volumes can failover across
machines. In addition, shared storage pools in a cluster are supported.
Q)
What about RAID? How do I use ReFS capabilities of striping, mirroring, or
other forms of RAID? Does ReFS deliver the read performance needed for video,
for example?
ReFS leverages
the data redundancy capabilities of Storage Spaces, which include striped
mirrors and parity. The read performance of ReFS is expected to be similar to
that of NTFS, with which it shares a lot of the relevant code. It will be great
at streaming data.
Q)
How come ReFS does not have deduplication, second level caching between DRAM
& storage, and writable snapshots?
ReFS does not
itself offer deduplication. One side effect of its familiar, pluggable, file
system architecture is that other deduplication products will be able to plug
into ReFS the same way they do with NTFS.
ReFS does not
explicitly implement a second-level cache, but customers can use third-party
solutions for this.
ReFS and VSS work
together to provide snapshots in a manner consistent with NTFS in Windows
environments. For now, they don't support writable snapshots or snapshots
larger than 64TB.