What replicate task uses:  all new files go with "nexttry" 0, rather than relying on "devcount".

CREATE TABLE needs_replicate (
   fid        INT UNSIGNED NOT NULL PRIMARY KEY,
   nexttry    INT UNSIGNED NOT NULL,
   INDEX (nexttry),
   fromdevid  INT UNSIGNED,             /* NULL means no preference */
   failcount  TINYINT UNSIGNED
   flags?                               /* one bit means corrupt, choose source where two files are the same md5?  reserved for future use. */
);

server_settings:
    'fsck_enable'   {off,locations,quick,full}   location=file_on only, quick=file_on + HEAD requests, full=contents
    'fsck_highest_fid_checked'  = <fidnumber>

update server_settings SET val=foo WHERE key='highest_fid_inserted' and val < foo;

CREATE TABLE fsck (
   fid        INT UNSIGNED NOT NULL PRIMARY KEY,
   nextcheck  INT UNSIGNED NOT NULL,
   INDEX (nextcheck),
)

# todo:  replicate_now command to make all needs_replicate files nexttry=0;
# todo:  fsck, if no copies, still puts in needs_replicate but with high nexttry time and of course no fromdevid.

# how often do recheck files?  --never, only when they kick it off.
# todo:  replication policy saying "not quite happy" goes into "needs_replicate" table for to-be-fixed-later
# todo: stat command to get count of rows in needs_replicate  (!repl replacement)

# provide command to drop fsck table to force global reindexing
# interface from fsck job to replicate job.  or do it ourselves sharing code.  (probably sharing code)
# perhaps command-line version is just running:
#    mogilefsd --run-only-job=fsck --foreground --verbose
#

while (1) {

    # create table if not exist.  (the fsck table)

    # while (find files to check from fsck table),
    #     randomize
    #     check them, inserting into needs_replicate or updating nextcheck time, or deleting if okay.

    # once no more files to check....

    # find files that are so new they don't have records in fsck
    while (max(file) > max(server_settings.fsck._highestfidcheck) && fsck enabled) {
        insert into fsck select fid, ? ? ? ?  from file where fid > max(fsck) order by fid limit 500
    }
}