[tahoe-dev] Object Health

[Greg Troxel]

Brad Rupp <bradrupp at gmail.com> writes:

> I am running the following command:
>
> ~/tahoe/bin/tahoe deep-check --repair --verbose my-alias:

I would include --add-lease, because the servers might be doing expiration.

> The output from repair #1:
>
> repair successful
> done: 11801 objects checked
>  pre-repair: 11725 healthy, 76 unhealthy
>  76 repairs attempted, 76 successful, 0 failed
>  post-repair: 11801 healthy, 0 unhealthy
>
> The output from repair #2:
>
> done: 11801 objects checked
>  pre-repair: 11789 healthy, 12 unhealthy
>  12 repairs attempted, 11 successful, 1 failed
>  post-repair: 11800 healthy, 1 unhealthy

This is a clue that your servers are unstable somehow; it isn't normal.
I would use tcpdump and see if connection are coming and going.

To measure without changing, I would do deep-check (with --add-lease)
without using --repair and see if you get stable output.

> As you can see, the first repair found and fixed 76 unhealthy
> objects. The second repair, approximately 12 hours later, found 12
> unhealthy objects and fixed 11 of them.

How many servers?  Are they all stably present, both uptime and
connectivity?

> Why would the second repair find 12 unhealthy objects?  I would have
> expected it to find 0 unhealthy objects given that the first repair
> was performed only 12 hours earlier.

Absent servers not being reachable, you are right.

> This is just one repair run out of many.  I can consistently get
> similar results.  I guess the deeper question is are the objects
> stored in Tahoe safe?  Or when I really need them due to a
> catastrophic event will I lose a handful of objects due to this?

So far your objects were repairable, so you haven't lost data.  But
there is IMHO something wrong.
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