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https://issues.apache.org/jira/browse/TS-436?page=com.atlassian.jira.plugin.system.issuetabpanels:all-tabpanel
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Phil Sorber updated TS-436:
---------------------------
Assignee: Miles Libbey (was: Crystal Qian)
> Documentation for variable hardware sector size support
> -------------------------------------------------------
>
> Key: TS-436
> URL: https://issues.apache.org/jira/browse/TS-436
> Project: Traffic Server
> Issue Type: Improvement
> Components: Documentation
> Affects Versions: 2.1.6
> Reporter: John Plevyak
> Assignee: Miles Libbey
> Labels: newbie
> Fix For: Docs
>
>
> TS-43
> Adds support for auto-detecting drives which have 4096 (well, between
> 512-8192) sector size
> and using that as the element of atomicity in the cache.
> Add (optional/hidden) config:
> CONFIG proxy.config.cache.force_sector_size INT
> to force a sector size (e.g. 4096) for ALL disks.
> SSDs and "advanced format" drives lie about their sector size and
> claim 512. The handling of this is still in flux in linuxland hence the option
> to force a particular sector size. Note: it is safe to force a higher size
> than the hardware supports natively as we still only count on atomicity
> in 512 byte increments.
> 4096 sector size drives formatted for windows will have partitions aligned on
> 63 512
> byte sector boundaries which will mean they will be unaligned.. There are
> workarounds, but
> you need to do some research on your particular drive. For example, some
> drives have a one
> time option to switch the partition boundary, others might require
> reformatting or repartitioning.
> To be safe in Linux you could just use the entire
> drive: /dev/sdb instead of /dev/sdb1 and TS will do the right thing.
> This feature should work fine when we get out of the difficult transition
> stage,
> in the mean time caveat emptor.
> Partitions formatted to support hardware sector
> size of more than 512 (e.g. 4096) will result in all objects stored
> in the cache to be integral multiples of 4096 bytes which will result in
> some waste for small files.
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