rsync(1) -chavzP --stats /path/to/local/storage
a fast, versatile, remote (and local) file-copying tool
-c, --checksum
       This  changes  the  way rsync checks if the files have been changed and are in need of a transfer.
       Without this option, rsync uses a "quick check" that (by default) checks if each file’s  size  and
       time  of  last  modification  match  between the sender and receiver.  This option changes this to
       compare a 128-bit checksum for each file that has a matching size.  Generating the checksums means
       that  both  sides  will expend a lot of disk I/O reading all the data in the files in the transfer
       (and this is prior to any reading that will be done to transfer changed files), so this  can  slow
       things down significantly.

       The  sending  side  generates its checksums while it is doing the file-system scan that builds the
       list of the available files.  The receiver generates its checksums when it is scanning for changed
       files,  and  will  checksum  any  file  that has the same size as the corresponding sender’s file:
       files with either a changed size or a changed checksum are selected for transfer.

       Note that rsync always verifies that each transferred file  was  correctly  reconstructed  on  the
       receiving side by checking a whole-file checksum that is generated as the file is transferred, but
       that  automatic  after-the-transfer  verification  has  nothing   to   do   with   this   option’s
       before-the-transfer "Does this file need to be updated?" check.

       For  protocol  30  and  beyond  (first  supported  in 3.0.0), the checksum used is MD5.  For older
       protocols, the checksum used is MD4.
-h, --human-readable
       Output numbers in a more human-readable format.  This makes big numbers output using larger units,
       with  a  K,  M,  or  G  suffix.   If  this  option was specified once, these units are K (1000), M
       (1000*1000), and G (1000*1000*1000); if the option is repeated,  the  units  are  powers  of  1024
       instead of 1000.
-a, --archive
       This is equivalent to -rlptgoD. It is a quick way  of  saying  you  want  recursion  and  want  to
       preserve  almost  everything  (with -H being a notable omission).  The only exception to the above
       equivalence is when --files-from is specified, in which case -r is not implied.

       Note that -a does not preserve hardlinks, because finding multiply-linked files is expensive.  You
       must separately specify -H.
-v, --verbose
       This  option  increases  the amount of information you are given during the transfer.  By default,
       rsync works silently. A single -v will give you information about what files are being transferred
       and  a  brief summary at the end. Two -v options will give you information on what files are being
       skipped and slightly more information at the end. More than two -v options should only be used  if
       you are debugging rsync.

       Note that the names of the transferred files that are output are done using a default --out-format
       of "%n%L", which tells you just the name of the file and, if the item is a link, where it  points.
       At  the  single  -v  level  of  verbosity,  this  does not mention when a file gets its attributes
       changed.  If you ask for an itemized list  of  changed  attributes  (either  --itemize-changes  or
       adding  "%i"  to  the  --out-format  setting), the output (on the client) increases to mention all
       items that are changed in any way.  See the --out-format option for more details.
-z, --compress
       With  this  option, rsync compresses the file data as it is sent to the destination machine, which
       reduces the amount of data being transmitted -- something that is useful over a slow connection.

       Note that this option typically achieves better compression ratios than can be achieved by using a
       compressing  remote  shell  or  a compressing transport because it takes advantage of the implicit
       information in the matching data blocks that are not explicitly sent over the connection.

       See the --skip-compress option for the default list of file suffixes that will not be compressed.
-P     The  -P  option  is  equivalent to --partial --progress.  Its purpose is to make it much easier to
       specify these two options for a long transfer that may be interrupted.
       This  tells  rsync to print a verbose set of statistics on the file transfer, allowing you to tell
       how effective rsync’s delta-transfer algorithm is for your data.

              The current statistics are as follows:

              o      Number of files is the count  of  all  "files"  (in  the  generic  sense),  which  includes
                     directories, symlinks, etc.

              o      Number  of  files  transferred  is  the count of normal files that were updated via rsync’s
                     delta-transfer algorithm, which does not include created dirs, symlinks, etc.

              o      Total file size is the total sum of all file sizes in the transfer.  This  does  not  count
                     any size for directories or special files, but does include the size of symlinks.

              o      Total  transferred  file  size is the total sum of all files sizes for just the transferred

              o      Literal data is how much unmatched file-update data we had to send to the receiver  for  it
                     to recreate the updated files.

              o      Matched data is how much data the receiver got locally when recreating the updated files.

              o      File  list  size is how big the file-list data was when the sender sent it to the receiver.
                     This is smaller than the in-memory size for the  file  list  due  to  some  compressing  of
                     duplicated data when rsync sends the list.

              o      File  list generation time is the number of seconds that the sender spent creating the file
                     list.  This requires a modern rsync on the sending side for this to be present.

              o      File list transfer time is the number of seconds that the sender  spent  sending  the  file
                     list to the receiver.

              o      Total  bytes sent is the count of all the bytes that rsync sent from the client side to the
                     server side.

              o      Total bytes received is the count of all non-message  bytes  that  rsync  received  by  the
                     client  side from the server side.  "Non-message" bytes means that we don’t count the bytes
                     for a verbose message that the server sent to us, which makes the stats more consistent.
Local:  rsync [OPTION...] SRC... [DEST]

Access via remote shell:
  Pull: rsync [OPTION...] [USER@]HOST:SRC... [DEST]
  Push: rsync [OPTION...] SRC... [USER@]HOST:DEST

Access via rsync daemon:
  Pull: rsync [OPTION...] [USER@]HOST::SRC... [DEST]
        rsync [OPTION...] rsync://[USER@]HOST[:PORT]/SRC... [DEST]
  Push: rsync [OPTION...] SRC... [USER@]HOST::DEST
        rsync [OPTION...] SRC... rsync://[USER@]HOST[:PORT]/DEST
source manpages: rsync