Re: [gentoo-user] new machine : (2) HDD or SSD ?

[Paul Hartman <paul.hartman+gentoo@gmail.com>]

On Sun, Jul 22, 2012 at 1:46 PM, Florian Philipp <lists@binarywings.net> wrote:
> Am 22.07.2012 20:35, schrieb Michael Hampicke:
>> Am 22.07.2012 19:46, schrieb Florian Philipp:
>>> Am 22.07.2012 19:30, schrieb Pandu Poluan:
>>>>
>>>> On Jul 23, 2012 12:05 AM, "Michael Hampicke" <gentoo-user@hadt.biz
>>>> <mailto:gentoo-user@hadt.biz>> wrote:
>>>>>
>>>>>> I have just a (maybe silly) question...
>>>>>> I saw on some forums that partitionning SSDs could slow down read/write
>>>>>> access.
>>>>>> Is it true or simply intox ?
>>>>>> On my sata HD, i have boot, /, usr and home separated partitions.
>>>>>> What do you think of it ?
>>>>>
>>>>> This could happen of the partitions on the SSD are not properly aligned.
>>>>> The guides I know on this subject are german, but thats no problem, just
>>>>> do a google search for something like "linux ssd partition alignment".
>>>>> There you will find all the ansers you need.
>>>>>
>>>>> If I remember correctly parted has a built-in alignment check.
>>>>>
>>>>
>>>> Even the venerable fdisk now properly align partitions, IIRC.
>>>>
>>>> Rgds,
>>>>
>>>
>>> cfdisk is one of the few that don't.
>>>
>>
>> Right, cfdisk was the one, but I always likes it's console 'gui' as it
>> was so easy to use. But cgdisk (of sys-apps/gptfdisk) is a good
>> replacement for cfdisk.
>>
>
> Good to know. cfdisk was my favorite, too.

You can still use it, you just have to specify the start sector
yourself and don't accept the default. :)

4MB is almost always a safe starting point to use for SSD or other
flash-based storage. (Most fdisk tools default now to 1MB which should
be safe for all HDDs but not necessarily the best choice for flash
storage because of erase blocks etc.) Unfortunately the exact perfect
alignment depends on the specific device you're using so there is no
catch-all solution. There are tools like flashbench will will try to
reveal the optimal settings via destructive tests.