Apache Access 日誌收到請求時間問題

請在 Ubuntu 14.04 的 Apache(2.4.7) 訪問日誌中查看接收請求時間的奇怪情況：

IP1 - - [14/Dec/2016:00:00:02 +0300] "GET /portal/get.php?filename=file1.mpg HTTP/1.1" 206 194292 "-" "Lavf53.32.100"
IP1 - - [14/Dec/2016:00:00:02 +0300] "GET /portal/get.php?filename=file1.mpg HTTP/1.1" 206 140716 "-" "Lavf53.32.100"
IP1 - - [14/Dec/2016:00:00:02 +0300] "GET /portal/get.php?filename=file1.mpg HTTP/1.1" 206 191396 "-" "Lavf53.32.100"
IP2 - - [13/Dec/2016:23:59:59 +0300] "GET /portal/get.php?filename=file2.mpg HTTP/1.1" 206 6010910 "-" "Lavf53.32.100"
IP2 - - [14/Dec/2016:00:00:03 +0300] "GET /portal/get.php?filename=file2.mpg HTTP/1.1" 206 189950 "-" "Lavf53.32.100"
IP2 - - [14/Dec/2016:00:00:03 +0300] "GET /portal/get.php?filename=file2.mpg HTTP/1.1" 206 191398 "-" "Lavf53.32.100"
IP2 - - [14/Dec/2016:00:00:03 +0300] "GET /portal/get.php?filename=file2.mpg HTTP/1.1" 206 237734 "-" "Lavf53.32.100"
IP2 - - [14/Dec/2016:00:00:03 +0300] "GET /portal/get.php?filename=file2.mpg HTTP/1.1" 206 194294 "-" "Lavf53.32.100"
IP3 - - [13/Dec/2016:23:59:34 +0300] "GET /portal/get.php?filename=file3.mpg HTTP/1.1" 206 5374262 "-" "Lavf53.32.100"
IP1 - - [14/Dec/2016:00:00:02 +0300] "GET /portal/get.php?filename=file1.mpg HTTP/1.1" 206 5465012 "-" "Lavf53.32.100"
IP1 - - [14/Dec/2016:00:00:06 +0300] "GET /portal/get.php?filename=file1.mpg HTTP/1.1" 206 184156 "-" "Lavf53.32.100"
IP1 - - [14/Dec/2016:00:00:06 +0300] "GET /portal/get.php?filename=file1.mpg HTTP/1.1" 206 121892 "-" "Lavf53.32.100"

任何想法為什麼時間沒有按升序排列？
這是 Apache 問題還是我的伺服器出了問題，或者不需要擔心這個？
我還需要在伺服器上檢查什麼？

日誌中記錄的時間是最初收到請求的時間。但是，直到請求完成，日誌條目才真正寫入。因此，當某些請求需要更多時間才能完成時，請求可能會出現亂序。

引用自：https://serverfault.com/questions/820828