/root filesystem performance improvements

[pleasantone]

Some research was done here[1] and adapted by the OpenElec raspberry pi folks for significantly increasing the SD card performance by block aligning the ext4 filesystem such that read/write/erases drop on sector boundaries.

While determining the actual block alignments (4k/8k/16k) might be a bit of a pain, we win at all three alignments if we start the root filesystem on a block that is a modulo of 32768 (16k at 512 bytes/block).

Then people can easily fine-tune ext4 sector sizes if you allow us access to the mkfs.ext4 options (e.g. someone with 4k alignment might do: -O ^has_journal -E stride=2,stripe-width=1024 -b 4096)

Thoughts?

[1] http://blogofterje.wordpress.com/2012/01/14/optimizing-fs-on-sd-card/

[hifi]

As raspbian-ua-netinst is a power user tool, I'm more than happy to add support for tuning mkfs.ext4 options in config. Patches welcome or I'll look at it later.

[pleasantone]

cool, working on it, making fdisk start at erase-page boundaries without hand tweaking is more amusing than I guessed..

[hifi]

@pleasantone, can you confirm @mcanevet's commit added this support?

[pleasantone]

Looks excellent from a visual review.  It turns out tweaking fdisk parameters was a bit more complex than I had anticipated and outside the scope of the installer (it required manual intervention and some iteration).  Please feel free to close this issue.

From: Toni Spets notifications@github.com
Reply: hifi/raspbian-ua-netinst reply@reply.github.com
Date: April 1, 2014 at 11:40:47 AM
To: hifi/raspbian-ua-netinst raspbian-ua-netinst@noreply.github.com
Cc: Paul Traina bulk+github@pst.org
Subject:  Re: [raspbian-ua-netinst] /root filesystem performance improvements (#21)

@pleasantone, can you confirm @mcanavet's commit added this support?

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[Mausy5043]

Just wondering. Would the use of f2fs achieve similar results regarding SD performance?

[diederikdehaas]

I don't know. I've timed various installations with various file systems and the settings mentioned above, but with those test the defaults produced the best results.
But that's not like a typical use.

[diederikdehaas]

The options are available and I have no intention of changing the defaults, so it's time to close this issue.