Re: Investigation: Is Your SSD More Reliable Than A Hard Drive?



On Fri, 05 Aug 2011 05:55:00 +0100, Mike Tomlinson <mike@xxxxxxxxxxxxx> wrote:

En el artículo <op.vzpqtvvrkd9x7s@fred>, Johny B Good
<invalid@xxxxxxxxxxxx> escribió:

However, what seems to be overlooked is the fact that,
unlike the situation with a real magnetic disk using 4K sectors, SSD
technology (being based on flash memory) cannot overwrite its 4k sectors
directly and has to use block erase before it can write fresh data.

Unfortunately, the erase block size is considerably greater than 4KB,
usually 128KB and up and it is to the erase block size that partitions
need to be aligned.

Do you have a cite for this, please? I can imagine it may have applied
to early flash memory but I'm sure the controllers are more
sophisticated than that now.


Ok Mike, as promised, a few links to articles/forum postings relating to SSD alignment.

https://wiki.archlinux.org/index.php/Solid_State_Drives

http://forums.freebsd.org/showthread.php?t=19093

http://forums.overclockers.co.uk/showthread.php?t=18259771

http://lists.opensuse.org/opensuse-factory/2009-08/msg00866.html

http://www.speedguide.net/articles/ssd-speed-tweaks-3319&print=friendly


http://www.ocztechnologyforum.com/forum/showthread.php?87427-Windows-partition-alignment-validation-tool-partinfo-(free)&s=36c9d77d73d37dd7f226696649326784


That last link has a small zipped Windows-partition-alignment-validation-tool download which works perfectly fine in win2k. Please take note of reference to adding an extra line to the batch file script to keep the command line box open (Pause > nul).

Furthermore, the lack of the Vista install DVD in the list of install media required to obtain a suitably aligned partition had me double checking that the Vista Recovery CD was indeed a Vista Recovery CD and not a W7 Recovery CD.

Although the Vista Recovery CD does indeed correctly partition an SSD this doesn't necessarily mean a Vista install DVD will. The Vista Recovery CD iso was made available by MS in response to issues raised by their Vista cursed customer base and most probably was compiled with the later win7 version of the partitioning utility.

I've no doubt that someone with time on their hands a spare SSD and a Vista install DVD to hand could verify or discount this assumption (I'd recommend that they also burn a Vista Recovery CD if they don't already have win7 or server2008 install media handy).

Although I haven't seen any hard evidence for the benefit of EB alignment, there certainly seems to be a consensus that this is a sensible precaution to take as well as echoes of your own sentiments regarding the sophistication of modern SSD controllers.

Considering how insignificant the 'wastage' is, it would seem foolish not to align the partitions to the EB. There's nothing to lose but quite possibly something to gain. For my part (especially as that 30GB Kingston SSD is considered as being 'old technology'), I'm playing safe in this matter. ;-)

--
Regards JB Good
.