[tahoe-lafs-trac-stream] [Tahoe-LAFS] #2346: cloud backend uses losts of expensive LIST requests

[Tahoe-LAFS]

#2346: cloud backend uses losts of expensive LIST requests
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 Reporter:  cloud_trouble               |          Owner:
     Type:  defect                      |         Status:  new
 Priority:  normal                      |      Milestone:  undecided
Component:  code-storage                |        Version:  cloud-branch
 Keywords:  cloud S3 cost optimization  |  Launchpad Bug:
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 The cloud backend uses lots of expensive LIST requests with an Amazon S3
 bucket from heavy use of GET Bucket. The GET Bucket request is billed as a
 LIST request and is 10 times more expensive than a GET Object request.

 These LIST requests can be a large portion of the cost of using an S3
 backed storage node. For example, my logs show 1.5 times as many GET
 Bucket requests as GET Object requests (with two storage nodes, one S3
 bucket and one desktop computer) and the cost exceeds storage, transfer,
 and ec2 costs.

 Here is some relevant code:
 https://github.com/LeastAuthority/tahoe-lafs/blob/cloud-
 rebased/src/allmydata/storage/backends/cloud/cloud_common.py#L426

 And relevant chat on IRC:

 <daira1> the list of shares is stored in a local database called the
 leasedb. that was added recently on the cloud branch, so I suspect we're
 not making optimal use of it yet
 <daira1> ISTR that zooko was arguing for treating the leasedb as
 authoritative as to whether a share exists, and I was arguing against for
 a reason that I can't remember right now. there's a ticket about it
 <zooko> Yes, the arguments about the trade-offs of treating leasedb as
 authoritative vs. advisory are encoded into tickets.
 <zooko> I seem to recall that treating leasedb as authoritative gets nice
 performance, including for this particular aspect, while trading off some
 other values.

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Ticket URL: <https://tahoe-lafs.org/trac/tahoe-lafs/ticket/2346>
Tahoe-LAFS <https://Tahoe-LAFS.org>
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