Questions about 5400 rpm drives and mirroring

[locutus]

I want to stream video files to my TV. I'm going to use 3 drives in 1 or more external enclosures.

1) Since I'm not running software on the drives, I don't need 7200 rpm drives. I could use 5400 rpm drives, right? They won't have any trouble streaming the files, right?

2) I was thinking of WD Blue drives. What about 3 of those?

3) I've never used mirror before. If I have 3 drives, I can mirror 1 drive to the other 2, giving me 3 identical drives. Is that right?

Thanks for any info.

[abolibibelot]

1) Since I'm not running software on the drives, I don't need 7200 rpm drives. I could use 5400 rpm drives, right? They won't have any trouble streaming the files, right?

The transfer speed of a HDD is influenced by the platter density more than the spindle speed, and most recent 5400 RPM models with a capacity higher than 1TB can reach 100MB/s easily, which should be more than enough for your purposes, unless you want to stream raw uncompressed footage...

2) I was thinking of WD Blue drives. What about 3 of those?

DR pros around here are heavily biased against Seagate, and tend to favor HGST drives. WD seems to be somewhere in the middle, reliability wise. “Blue” used to designate the regular desktop drives, with a spindle speed of 7200 RPM (I've had two WD “Blue” in 640GB, bought in 2009, one failed last summer, the other one is still perfectly operational), apparently they completely changed their branding, so I could say nothing specific about current “Blue” drives.

3) I've never used mirror before. If I have 3 drives, I can mirror 1 drive to the other 2, giving me 3 identical drives. Is that right?

Do you mean, as a RAID 1 array ? Or simply cloning a drive as a one time operation ? What is the purpose of having 3 identical drives ? If it's for data safety, it might be a tad overkill, especially for streaming movies, but hey, if you have too much money, there are worse ways to spend it...

[locutus]

The transfer speed of a HDD is influenced by the platter density more than the spindle speed, and most recent 5400 RPM models with a capacity higher than 1TB can reach 100MB/s easily, which should be more than enough for your purposes, unless you want to stream raw uncompressed footage...

They're movies and TV shows. mp4, mkv, avi. So they're are all compressed.

Do you mean, as a RAID 1 array ? Or simply cloning a drive as a one time operation ? What is the purpose of having 3 identical drives? If it's for data safety, it might be a tad overkill, especially for streaming movies

Like I said, I've never used mirror. I assumed that once a drive is mirrored, if changes are made to the main drive, Windows will update the mirror. If the mirror is turned off, it will be updated when it's turned on. Is this not how it works? The reason for 3 drives is to have backups. Why would 3 drives be overkill? I don't want everything on only 1 drive and then it fails and 1 backup doesn't seem enough. There will be many videos so I thought having 2 backup drives made sense.

[abolibibelot]

They're movies and TV shows. mp4, mkv, avi. So they're are all compressed.

Yes, of course, that's what I meant : it's very unlikely to be an issue, since the video files in playback format are always compressed, and with a bitrate far below the throughput of even the slowest HDDs currently available. Just make sure you don't use enclosures in USB 2.0 : it limits the transfer speed to about 30MB/s, which could cause issues with high bitrate blu-ray copies (and would considerably slow down the file transfer operations anyway) ; even if the average bitrate is below that threshold, videos in H.264 / H.265 (and Xvid but it should be considered obsolete by now) are encoded with a variable bitrate, so complex scenes can require significantly more. You can check that with a tool called Bitrate Viewer if you're curious : I just made a test, with a MKV transfer of the movie The Dark Knight rises, total size 13.7GB, average video bitrate 8952kbps, average global bitrate (according to MediaInfo) 12mbps, but the video bitrate peaks at almost 37mbps (that's without the audio), which is actually 4.6MB per second since the bitrates are measured in bits, not bytes, so that particular file can be read with no hiccup in USB 2.0, but some video files could reach higher values, especially with 4K+ resolutions on the horizon. It shouldn't be a problem for a long time in USB 3.0 or eSATA.

Like I said, I've never used mirror. I assumed that once a drive is mirrored, if changes are made to the main drive, Windows will update the mirror. If the mirror is turned off, it will be updated when it's turned on. Is this not how it works? The reason for 3 drives is to have backups. Why would 3 drives be overkill? I don't want everything on only 1 drive and then it fails and 1 backup doesn't seem enough. There will be many videos so I thought having 2 backup drives made sense.

Is this a Windows integrated feature that you plan on using ? If so, I don't know about it. But yes, generally speaking, mirroring means that the contents are automatically and continuously duplicated. As far as I know you can't use a RAID configuration if one or more drives in the array are sometimes disconnected (they must be on or off at the same time). A software mirroring on the other hand should do what you want, but I've never used any in an automated configuration.
For me it would seem overkill since movies are easy to find nowadays, and in the unlikely event that the main drive and one backup would fail at the same time it wouldn't be a disaster, compared with losing personal pictures or writings or anything creative that can't be re-created. But if you already have a solid backup solution for your personal files, and movies are very important to you, and you can afford to have three mirrored drives, by all means do it.

[maximus]

I would like to add my 2 cents about mirroring 3 drives. Assuming you are using windows, I would suggest putting 2 of the drives in a RAID 1 configuration (mirroring, also known as fake raid since it is software based). Use the 3rd drive as a backup copy of the mirrored RAID 1 that you update regularly. Look into robocopy for how to make a mirrored file backup with only updating changed files. And if you go as extreme as me, you can also use shadowspawn with robocopy for making a backup while the RAID 1 is being used and could possibly undergo changes during the backup.

FYI if you remove one of the RAID 1 drives it will lose sync. When you put it back it will need to re-sync the entire drive, which can take awhile and slow everything down that time.