Data Domain：MTREE 复制在初始化期间显示不正确的Bytes_remaining

MTREE 复制在初始化过程中为复制过程中从未使用过的旧 MTREE 显示不正确的字节。

The following MTREE has been used [# mtree list]:
/data/col1/support           5965.4   RW

统计信息显示使用上述步骤创建新的 MTREE 复制后剩余 92 TB 数据：

# replication show detailed-stats rctx://1

CTX:1
Destination:                               
mtree://dd-dr.support.com/data/col1/support
Network bytes sent to destination:          2,287,577,928
Pre-compressed bytes written to source:     92,046,090,413,266
Pre-compressed bytes sent to destination:   2,860,770,559
Bytes after synthetic optimization:         2,860,770,559
Bytes after filtering by destination:       2,253,845,068
Bytes after low bandwidth optimization:     2,253,845,068
Bytes after local compression:              2,258,791,288
Pre-compressed bytes remaining:             92,043,229,642,707   <----
Compression ratio:                          1.3
Sync'ed-as-of time:                         (initializing)

虽然底层注册表项显示的字节更准确：

repl.001.src_host = dd-prod.support.com
repl.001.src_path = /data/col1/support
repl.001.dst_host = dd-dr.support.com
repl.001.dst_path = /data/col1/support
repl.001.progress.task_name = initializing 3/3
repl.001.progress.init_vbytes = 5991145719813   <---

从 ddfs.info：
初始虚拟字节估计看起来没问题：

09/21 10:58:45.157 (tid 0x2b0e208796e0): repl ctx 1: mrepl_create_init_snap creating initial snapshot.
09/21 10:58:48.068 (tid 0x2b0e208796e0): repl ctx 1: estimating init vbytes as 5991145719813
09/21 10:58:48.995 (tid 0x2b0e208796e0): repl ctx 1: Using init_resync_snapid 1433317767:1886. Total snap count = 2, curent snap cnt = 0.

几分钟后，正常过程 mrepl_sends 开始出现：

09/21 11:19:04.136 (tid 0x327e760): repl ctx 1:3: mrepl_send_file: file 30:0:ac66:0:a30e9f46:556eb187:1d74 took 218 sec, net throughput 297 KB/s, virtual throughput 290 KB/s, refs_sent 7575, refs_features_sent 0, segs_sent 0, segs_features_sent 7575, size 63416832, vbytes 63416832, nbytes 64858812 (recid 361) (ch-xor 0x98f3c7e9) (hole_seen FALSE)
09/21 11:19:59.031 (tid 0x2b0e2083cde0): repl ctx 1:16: mrepl_send_file: file 30:0:ac68:0:fccc10a6:556eb187:1d74 took 237 sec, net throughput 286 KB/s, virtual throughput 280 KB/s, refs_sent 7908, refs_features_sent 0, segs_sent 0, segs_features_sent 7908, size 66419200, vbytes 66419200, nbytes 67938672 (recid 363) (ch-xor 0x462a1211) (hole_seen FALSE)

下一次出现 vbytes_remain 显示不同的大小：

09/21 11:28:02.246 (tid 0x2b0e096ba050): repl ctx 1: mrepl_stats_local: vbytes_remain: 92036838018199

这就是设计为计算剩余逻辑字节的复制方式。每次用户开始复制某些较旧的 MTREE 时，都会观察到此不匹配。但是，这并不表示 MTREE 复制会复制此数据，它仅复制 MTREE 的当前大小，如下所示： init_vbytes_remain。

初始化阶段结束后，重置 vbytes_remain 更改为 0 并更新 vbytes_written_and_replicated 使用 cum_raw_bytes 因此，后续备份不会显示不切实际的统计信息，而是仅报告接收的新数据。