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Re: Calculating optimal disk partitions
From: |
craig |
Subject: |
Re: Calculating optimal disk partitions |
Date: |
Thu, 9 May 2013 07:20:19 -0500 (CDT) |
On Wednesday, May 8, 2013 16:46, "Chris Murphy" <address@hidden> said:
> On May 8, 2013, at 2:37 PM, address@hidden wrote:
>
>> On Wednesday, May 8, 2013 13:17, "Chris Murphy" <address@hidden> said:
>>
>> Thanks for responding Chris!
>>
>>> On a 512byte physical and logical sector hard drive, the messages can be
>>> ignored.
>>> Alignment isn't an issue.
>>
>> Wouldn't the generation of an error message, when no error condition exists,
>> be
>> considered a bug? At the very least I would think it would be undesirable.
>
> It's an older version of parted. I'd try it with 3.1. In any case, it's
> difficult
> because while 512B physical/logical sector drives should default to an
> alignment
> value of 1 sector, this probably isn't good for most SSDs which claim a 512B
> physical/logical sector size. The way it works now by default is to align on
> 1MB
> boundaries regardless of the physical sector size.
Thanks Chris, excellent point about the version. I stick with Debian's packages
whenever I can, but I certainly don't mind trying the latest version of parted.
I will let you know how that goes. In the meantime, do you mind if I post a
pointer to our conversation here back on the Debian User list for anyone that
might be following it there?
>
> It's possible in your case the warning is about another partition which isn't
> aligned, rather than the new one you're trying to create. If that's the case,
> the
> error message is misleading.
>
>>
>> What about a 4096 physical sector drive?
>
> Alignment on a 4Kn AF HDD is also a non-factor. There's nothing to align. But
> I
> still think the default is 1MB alignment with new versions of parted. As a
> data
> drive, they work. For boot drives, even recent firmware, let alone older
> firmware,
> don't like them at all.
>
> For 512e AF HDD, alignment is a considerable factor depending on the firmware
> implementation. It's best to align.
I would be more than happy to put together any helpful documentation if you or
someone else would give me some guidelines on what to put in it.
>>
>>> For SSDs which effectively lie about their physical sector size, the
>>> consequences
>>> of miss alignment are variable the firmware.
>>
>> If mis-alignment can negatively impact performance, I would expect a
>> documented
>> procedure on avoiding it. Or is my expectation out of line? I certainly
>> wouldn't
>> mind helping document the procedure if I could get a clear understanding on
>> how
>> what the procedure is.
>
> It would be nice if it worked this way, but in reality solid state storage is
> in
> flux on both a physical level, as well as a firmware (the thing most
> responsible
> for the logical abstraction from the physical drive). Firmware makes a huge,
> huge
> difference in SSD behavior.
>
>
> Chris Murphy
Most appreciatively,
Craig
Sent - Gtek Web Mail
- Calculating optimal disk partitions, craig, 2013/05/08
- Re: Calculating optimal disk partitions, Chris Murphy, 2013/05/08
- Re: Calculating optimal disk partitions, craig, 2013/05/08
- Re: Calculating optimal disk partitions, Chris Murphy, 2013/05/08
- Re: Calculating optimal disk partitions,
craig <=
- Re: Calculating optimal disk partitions, Chris Murphy, 2013/05/09
- Re: Calculating optimal disk partitions, craig, 2013/05/10
- Re: Calculating optimal disk partitions, Ulf Zibis, 2013/05/10
- Re: Calculating optimal disk partitions, Chris Murphy, 2013/05/11
- Re: Calculating optimal disk partitions, craig, 2013/05/14
- Re: Calculating optimal disk partitions, Chris Murphy, 2013/05/14