New to RAID

[bluestarCVO]

Hello everyone!

I am getting an 8-bay enclosure shipped to me tomorrow, and will be setting up a RAID server for the first time. Originally I had planned on just going with a RAID 5 setup, but after doing some research I discovered that this might not be my best option.

My question is to those of you using RAID setups: What RAID # are you using? Will RAID 5 be sufficient for me? I will be using it primarily for media streaming to my Boxee Boxes. At some times I may possibly be streaming HD video to two or more devices at one time. Can RAID 5 handle this without a hiccup? Is there another RAID setup I should consider? Any other suggestions or helpful info?

I would love to hear about what setups you all are using.

Thanks!

[mcompeau]

There is a lot of "opinion" in your question, so you may get a wide variety of answers.

here is my opinion;

RAID5 should be fine. You get the best performance, while still have redundancy. You can lose 1 disk at a time, and not lose any data.

Not sure what raid levels your device supports, but since it's 8 bays, i suspect raid5 will be your best choice.

also, streaming movies, in the grand scheme of things, is not heavy with I/O transactions. a raid5 with regular drives can keep up with streaming a movie without blinking. If you were running multiple read and writes to the array at the same time, then all the other factors come into play like raid level, drive speed, etc.

[bluestarCVO]

I plan on filling it with WD Caviar Black 2 TB drives. I knew it could stream one HD movie at a time with no problem...my USB hard drive can do that. But can I stream up to 3 HD movies at one time from this RAID 5 array without any problems? Also, anyone using RAID 5, what kind of read/write rates are you getting?

[megachirops]

You are going to be limited by the network speed more than drive speed. Gigabit ethernet is good for at most about 112MB/s. So there's really not a lot of reason to spend the Gigabucks on Caviar Blacks. 5400 RPM Green drives will more than saturate the network connection.

As for how many streams you can do at once, that depends on the bitrate of the files. But you should have no problem doing 3 streams at once. I had a 4-drive raid5 that had no problem serving multiple streams with 4x Samsung HD203WI.

[bluestarCVO]

You are going to be limited by the network speed more than drive speed. Gigabit ethernet is good for at most about 112MB/s. So there's really not a lot of reason to spend the Gigabucks on Caviar Blacks. 5400 RPM Green drives will more than saturate the network connection.

As for how many streams you can do at once, that depends on the bitrate of the files. But you should have no problem doing 3 streams at once. I had a 4-drive raid5 that had no problem serving multiple streams with 4x Samsung HD203WI.

Yeah, I had thought about going with the Caviar Greens, but I read many bad reviews concerning using those drives in a RAID setup. Everyone said to stay away from them. Also, there is the issue of them spinning down. I would rather not use a drive that I cannot keep spinning at all times.

Do you personally have experience with using the green drives in a RAID setup?

[voip-ninja]

I am using green Seagate 5900RPM LP drives in my Synology setup. It runs a hybrid raid system that allows you to mix and match drive sizes but since all of my drives are the same size it is essentially a RAID-5 setup. The advantage of green drives is that the larger number of disks you have the better the power savings. 3-4 watts per disk doesn't sound like much until you have a pile of them. If you have 8 discs and use green drives over black drives you would potentially save 30 watts or more, which adds up to about 300 kwh per year of power ($30-$60 depending on where you live).

With 8 drives the only risk you have of going with RAID-5 is that if you suffer a 2nd disk failure before a bad disk is replaced then you will potentially lose the data.

The concern really centers around the idea that there are "batches" of drives that might all fail relatively soon within the same time frame (since the drives are all ordered at the same time it increases the chance they are part of the same batch). Statistically I have never seen anything that really backs this up. It is all based on anecdotal reports from users of multiple drives failing quickly from the same batch.

If you stick with RAID-5 then I would strongly recommend setting up an email alert so that you know as soon as a disc is failing. Secondly, I would ALWAYS have a spare drive in hand onsite for RAID-5 so that you can replace the failed disk immediately without delay. Another way to do this is to do RAID-5 plus hotspare in which a drive is populated but unused until a disk failure is detected, then that drive is automatically built into the array with no user intervention.

An alternative for you is to do RAID-6. You will lose some capacity but the speed is about the same and RAID-6 can tolerate failure of up to two disks.

Me personally, I just do the SHR RAID-5 equivalent and have a spare disc onsite.

The system is bloody fast and can stream 3 BD MKV files simultaneously. I should see if I can get away with doing 4, which is a possibility with this setup I've got.

[Cheddoleum]

You are going to be limited by the network speed more than drive speed.

Depends on the type of enclosure and host connection. I've actually seen 8-bay USB2 RAID enclosures, which is completely silly unless performance is not an issue. USB2's theoretical max is 480mbit/s (i.e. 60mByte/sec) and you never get anywhere near achieving that in real life. For implementation reasons even firewire 400 is better than USB2, despite the lower marketing number. Best performance in an external enclosure is usually achieved with a hardware raid controller (either in the host or the enclosure itself) and an eSata or SAS connection. If the hardware raid is in the enclosure, a firewire 800 connection will probably be good enough to saturate a GigE network. Worst imaginable scenario is a JBOD enclosure, host-based software RAID and a USB connection.

[megachirops]

Yeah, I had thought about going with the Caviar Greens, but I read many bad reviews concerning using those drives in a RAID setup. Everyone said to stay away from them. Also, there is the issue of them spinning down. I would rather not use a drive that I cannot keep spinning at all times.

Do you personally have experience with using the green drives in a RAID setup?

Not personally, no. I tend to shy away from the true "green" type drives since I hate waiting for things to spin up in general

But I do just stick to the cheaper 5400 rpm drives for my NAS boxes since they have no problem keeping up with a network connection.

I'll also second the opinion of voip-ninja that you might want to consider a R5 + Hot Spare or R6 setup with 8 drives. That's the number where I start to get nervous about a 2nd drive failing at a "bad time". The current box I built has room for 12 drives, but only has 6 currently populated. Beyond 6 I'll be switching to R6 or adding a Hot Spare (haven't decided yet).

[aaronwt]

I plan on filling it with WD Caviar Black 2 TB drives. I knew it could stream one HD movie at a time with no problem...my USB hard drive can do that. But can I stream up to 3 HD movies at one time from this RAID 5 array without any problems? Also, anyone using RAID 5, what kind of read/write rates are you getting?

I have several RAID 5 setups that all use the WD green drives which run at 5400 rpm. They have zero difficulty streaming three High bitrate BD ISOs concurrently to my media players. For read speeds I get between 500mbps and 700mbps depending on the setup. For write speeds I get between 300mbps and 500 mbps depending on the setup.

Another option to consider is an unRAID system. I just set one up this past weekend and will eventually be switching the drives from one of my RAID 5 setups to my unRAID setup to give me more capacity with around 19 to 22 green drives. I still haven't decided on a final configuration.

I also have a WHS setup that uses thrity one green drives(5900rpm and 5400rpm) with 22 over USB. Even though my WHS has slower read/write rates than my RAID5 setups, it also has zero difficulty streaming three high bitrate BD ISOs concurrently to my media players.

I have not tested my unRAID setup yet to see how many high bitrate BD ISOs I can stream concurrently.

[planktonamor]

So I have a slightly different take...I have 2 Netgear ReadyNas Duos. I determined for backup sake, I would stick to Raid 1 and mirror the drives. I have 3 2TB drives for each, and one drive I swap out every so many months from an array and ship off to a family member for backup...they return 1 and I allow it to re-mirror. I looked at getting a 4+ drive setup and going RAID5, but if my house burns to the ground, or gets broken into, I never want to try and rebuild my collection from scratch. I have spent way too much time converting movies and audio, and taking pictures to go through it. I get great throughput. I have cat6 run through the house with a GB switch pushing the data out. I have had 720p pushed out from the same nas to multiple devices. I have never had an issue. I have 2 BB, and a mac mini running Plex to stream outbound from the network to my ipad and android phone. Works great.

Good luck