我想将gridfs（db）从一台机器复制到另一台机器。我们使用copydb命令。
> db.runCommand({copydb:1,fromhost:"192.168.1.90",fromdb:"fs_photos",todb:"fs_photos"})
{
"errmsg" : "exception: BSONObj size: -791766910 (0x8298CED0) is invalid.
Size must be between 0 and 16793600(16MB) First element: \u0014(\u0003: Object
Id('2800b83401d09a00301401da')",
"code" : 10334,
"ok" : 0
}
我检查了fs_photos(fromdb,140G)最大文件长度：
> db.fs.files.find({},{"length":1}).sort({"length":-1}).limit(5)
{ "_id" : "527156688f75550f14cdbe44", "length" : NumberLong(1369101) }
{ "_id" : "8197434919771504494", "length" : NumberLong(937048) }
{ "_id" : "7022162555617835884", "length" : NumberLong(893162) }
{ "_id" : "15191928400030169903", "length" : NumberLong(785255) }
{ "_id" : "18167776422270657585", "length" : NumberLong(777711) }
是我的db错误？