LinuxQuestions.org - RAID 5 data loss for weird reasons

ok so i ran into an interesting problem this weekend and wondering if i did something to cause it or not or why it might have happened.

so lets go back a few months in October i built this RAID 5 array using mdadm that included 4 1 TB Hitachi disks and copied a bunch of data (200 GB) from my old data drive to my shiny new RAID array. that went all fine and then later i got a bunch of data from some and copied it onto my array.

fast forward to this weekend. i was fooling around behind my systems and accidentally pulled the plug on my server. when it restarted one of the disks dropped out of the array for some reason. so i lated added it back and it resynced it and thought was all fine and dandy but i was wrong. i went to watch a movie on my server and any of the movies that i copied over in that second wave dont work outright or are very skippy or are a full file size but are only 4 or 5 seconds long but all of the data that came over in the first wave is totally fine. i have watched many movie from the first wave since then and they are completely fine.

any idea what would have caused that to happen why the old data would be fine but the new data is all corrupt in some way. its just kinda angering to have to copy this data back from friends when the thing thats supposed to make RAID 5 epic is that you have data security of one drive dies but it sadly didn't happen this time. i might put the disks into raid 10 to prevent this from happening again.

any ideas guys?

--Jezzirolk