Re: Dysk SSD jako systemowy C:\ - czy to dobry pomysł?

Dnia Tue, 9 Feb 2010 09:29:56 +0100, Latet napisał(a):

>> Ręczny partition alignment jest w przypadku XP i SSD niezbędny.
>
> A jak się to robi? Czym? I kiedy (spod Windows?).
> Czym jest ten partition aligment w ogóle? Czym się różni od normalnego
> podzielenia dysku na partycje?

Bez problemu wykonasz to spod BootIt (sorry za przydługi cytat autora
programu):

"Info for new drives with 4K sectors and WD "Advanced Formatting"

For some reason many users are thinking there is something special about
these new drives with internal 4K sectors and that they require advanced
formatting" to function properly. Let me just nip it in the bud now -
this is mainly marketing BS.

This should all be obvious to anyone with basic knowledge of drives/file
systems and the link. Here's some simple brief information:

What's the deal with the 4K sectors?

A sector is the smallest unit/block of data a drive can transfer. A
traditional hard drive has used 512 byte sectors and the plan to change
to a larger internal sector size has been in the works for years and
now there are drives that are using 4K sectors. The larger sector
sizes allow there to be more data on the same platter because there is
a gap between each sector (including the ECC data). These drives are
still fully compatibly with all existing software and operating systems
because they (properly) provide a 512 byte sector view and internally
handle read/writing in 4K chunks using read-modify-write. With proper
caching technology (built into the drive) the affects of this should be
negligible on typical desktops.

What about this alignment stuff?

Alignment has to do with where the partitions and data are located on
the drive. Obviously the "optimal" location is where all data to be
read/written are contained in the least number of sectors; however, it's
marketed simply as aligning partitions to the size of a sector (or block
for devices not using sectors). The reality is you may have a more
optimal configuration or setup if the partitions are not aligned to the
size of a sector - what matters is where and how IO occurs on the drive
which is dependant on the applications (including OS) use of data, file
system in use, the file system driver implementation, and any cache
manager implementation.

On the application side of things, one given is the OS paging file which
can be heavily used by the OS. The OS will read/write an entire page
which is 4096 bytes (4K) so having that file aligned to a sector size is
probably the biggest single alignment factor on a typical desktop
computer. For that file to be aligned, the clusters of the file system
need to be aligned (see below). While we're talking about the page
file, if your file system cluster size is < 4K you'd also want to ensure
that the page file is not fragmented or that could affect performance as
well.

For the file systems, NTFS clusters (allocation units) occur starting at
the start of a partition so if that partition is aligned on a sector
size, so will a cluster. For FAT the data may not be aligned even if
the partition is aligned on a sector size. However, you can use BootIt
Next Generation (BING) to format a FAT/FAT32 partition using "align for
NTFS" which will be aligned; you can also use BING to align an existing
FAT/FAT32 partition using its "slide" / "align for NTFS only" option.
BING is located at
http://www.terabyteunlimited.com/bootit-next-generation.htm

However, even if a cluster is sector aligned, it doesn't mean the file
system driver is going to read/write entire clusters at a time (in fact
that would normally be a waste of time and slow file access way down).
The only time you will see that is if either the file system driver is
poorly implemented, or for security the writes on newly allocated
clusters are zero padded (to end of new cluster) for security.

Another factor is a cache manager. If this cache manager reads or
writes entire clusters (or multiple of clusters) then having a cluster
aligned with a sector size will be optimal for the cache manager and
hence anything that uses it.

What's the bottom line on alignment and Windows?

Due to the cache manager and paging file it's probably best that you
align your partitions (particularly on heavy used servers/systems). You
can use BootIt Next Generation to align your new or existing partitions
by enabling its Align 2048 setting (you should also disable Align on
End, enable Align MBR End HS - see manual for details at
http://www.terabyteunlimited.com/support-bootit-next-generation.htm )
before creating the partition or before using its slide (move) option to
move the partition location.

However, if your partitions are not aligned or you don't want to align
them then simply don't worry about it because the system will continue
to function. If you find that the performance is not as expected then
align them at your convenience to see if that was the cause of your
performance issues."

-- 
M.   [Windows Desktop Experience MVP]
/odpowiadając na priv zmień px na pl/
https://mvp.support.microsoft.com/profile/Michal.Kawecki