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On Tue, 6 Feb 2007 12:20:26 -0600 |
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"Boyd Stephen Smith Jr." <bss03@××××××××××.net> wrote: |
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|
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> On Tuesday 06 February 2007, Mikko Husari <husku@×××××.net> wrote |
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> about 'Re: [gentoo-desktop] disk partitioning': |
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> > hmm, im really new to all that lvm stuff but i think i have a |
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> > general idea about it, does it reduce performance at all? |
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> |
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> Yes, but it's a completely insignificant amount compared to the |
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> additional flexibility it gives. Commercial UNIXes (HP-UX and AIX) |
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> have been defaulting to LVM for years, if not decades. |
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|
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LVM works by dividing the disk into "physical extents" (the size of |
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which are configurable on volume group creation), thus it is not |
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guaranteed that all the data contained within a logical volume will be |
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in one contiguous area on the disk. If this is the case, then the disk |
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head will spend more time seeking, increasing the latency of a |
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read/write operation. You can mitigate this on a per partition basis by |
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specifiying '--contiguous y' when creating a logical volume with |
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lvcreate. |
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|
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If you do decide to use a separate partition for portage then it is |
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sensible to specify a block size of 2048 bytes when you format it |
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(this is the -b option, at least for mkfs.ext* and mkreiserfs). As most |
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files in the tree are ~2KiB, there is a significant amount of |
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wastage with the default blocksize of 4096 bytes. It reduced the |
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filesystem usage of the tree on my system from ~500MiB to ~250MiB, if I |
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recall correctly. |
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|
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--atj |
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-- |
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