[dm-devel] [PATCHv4 00/15] dm-zoned: multiple drive support

[Hannes Reinecke]

On 6/3/20 12:27 AM, Mike Snitzer wrote:
> On Tue, Jun 02 2020 at  7:09am -0400,
> Hannes Reinecke <hare at suse.de> wrote:
> 
>> Hi all,
>>
>> here's the second version of my patchset to support multiple zoned
>> drives with dm-zoned.
>> This patchset:
>> - Converts the zone array to using xarray for better scalability
>> - Separates out shared structures into per-device structure
>> - Enforce drive-locality for allocating and reclaiming zones
>> - Lifts the restriction of 2 devices to handle an arbitrary number
>>    of drives.
>>
>> This gives me a near-perfect scalability by increasing the write
>> speed from 150MB/s (for a cache and one zoned drive) to 300MB/s
>> (for a cache and two zoned drives).
>>
>> Changes to v1:
>> - Include reviews from Damien
>> - Reshuffle patches
>> Changes to v2:
>> - Add reviews from Damien
>> - Merge patches 'dynamic device allocation' and
>>    'support arbitrary number of devices'
>> - Fix memory leak when reading tertiary superblocks
>> Changes to v3:
>> - Add reviews from Damien
>> - Add patch to ensure correct device ordering
> 
> I've picked this series up for 5.8 (yes, I know it is last minute).  But
> I saw no benefit to merging the initial 2 device step in 5.8 only to
> then churn the code and interface to support an arbitrary number of
> devices in 5.9.  Easier to support one major update to the code now.
> 
> As such the target's version number was _not_ bumped from 2.0.0 to
> 3.0.0.
> 
> I tweaked various patch headers (_please_ "dm zoned" instead of
> "dm-zoned" in commit subjects, also don't ever say "we" or "this patch"
> in a commit header... if you do, I am forced to rewrite the header).
> 
> BTW, just so I feel like I said it: all these changes to use additional
> device(s) really seems like a tradeoff between performance and reduced
> MTBF -- there is increased potential for failure with each additional
> device that is added to the dm-zoned device... there I've said it ;)
> 
"We" (sic) are fully aware. And I'm looking into it.

Thanks for merging it. Most appreciated.

Cheers,

Hannes
-- 
Dr. Hannes Reinecke            Teamlead Storage & Networking
hare at suse.de                               +49 911 74053 688
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