HP N54L + 8GB ECC + 4x4TB. What RAID?

[shimian5]

I am repurposing two of the Seagate 4TB drives from my ReadyNAS and 2 new drives, into a newly purchased N54L.

I've already ordered an additional 4gb DIMM to bring my total of ECC RAM up to 8GB.

I am now just trying to figure out if I am better suited for RAIDZ2 or something else...

The unit will be a home NAS used for streaming high bit-rate movies across a 1GB LAN + AC1750 WiFi.

I am more concerned with read than write, today with the ReadyNAS I only average ~40MB/s.

My biggest holdback for RaidZ2 is how wasteful it is with 2 drives, and if I decided to add 2 more later, I have to destroy/rebuild. I don't really need the capacity, and after buying the N54L and 2 more drives, don't feel like buying 2 more @ $150 a piece).

RaidZ1 is apparently just too dangerous...

Thoughts?

 

[cyberjock]

You've got 4GB of RAM. That means pool performance will be horribad. Not surprisingly, it's not fast. I'd expect when you get more RAM you will see performance take a significant leap. You can put 16GB in the N54L, so if you haven't bought the RAM yet consider buying a 8GB stick instead. Once you get the RAM then stop and assess the performance of the pool. Until then you're just complaining about stuff that we already know (and technically 4GB of RAM isn't even the minimum for the OS and is risky).

I'd do RAIDZ2. Mirrors will also work, but you are technically less safe because two failed disks in the same mirrored vdev would mean the end of your pool.

Hope this helps. :)

 

[shimian5]

It has 8gb, it's in my title.

It shipped with 4gb and has another 4gb on the way. With memory prices where they're at, I'll wait on an 8gb stick.

Back to the RAID type. I just think z2 with 4 disks feels wasteful, but I suppose no more than I'm used to with a raid1 today.

 

[HeinzApfel]

RaidZ1 is apparently just too dangerous...
Thoughts?

You should be aware that there is a hacked BIOS available, that enables the CD-ROM SATA to full speed.
This way I have 5 drives in my N54L.

 

[shimian5]

You should be aware that there is a hacked BIOS available, that enables the CD-ROM SATA to full speed.
This way I have 5 drives in my N54L.

5 drives is suboptimal though for RaidZ2 from what I've read? I'd get a little more space out of it, but at what performance cost?

Or is it negligible for NAS use (only making it self apparent with things like ESXi iSCSI or NFS?)

 

[Ericloewe]

For file serving on a small scale, there shouldn't be a problem, especially with compression on.

 

[shimian5]

I don't think I intended to use compression, unless there is a compelling reason to do so.

So is the consensus that although 6 drives is ideal, I would still be okay with 5, and it would be a more efficient use of RaidZ2? If so I will purchase a 5th drive and get it built. I just want to make sure that a 5 drive array, plus RaidZ2 won't be disappointing from a read/write perspective.

At some point I will also get the RAM up to 12GB, but for now will stick with 8GB ECC Unbuf, until I can find something.

 

[Ericloewe]

Well, there's no compelling reason not to do compression, unless the CPU can't handle it (even then, for FSB-limited processors, reducing the amount of data transferred to/from the drives may improve system performance, if compression doesn't require additional memory accesses).

 

[shimian5]

Fair enough! I will definitely test the solution with compression. I know the processor in the N54L is a little bit dainty, so I will make sure it doesn't appear to be taxing it too hard.

Now for a consensus on 5 vs 4, and I'll be ready to go (as soon as the dang drives come!)

 

[gpsguy]

Some users squeeze 2 3.5" disks in the ODD bay and use the eSATA connector. You'd need to use a hacked BIOS.

It's too bad you already bought the 4Gb stick. With only 2 slots for RAM, upgrading in the future will require you to replace your current RAM.


Sent from my phone

 

[shimian5]

It was inexpensive enough that I could flip it back on eBay for near what I paid.

I am already pretty invested in this, and I don't really want to drop ~300 on 2 more drives, which is why I am trying to see if I can get away with 5. I don't need the space of 6, honestly the space of 4 is enough, it's just wasteful and not very future thinking.

If 5 performs within reason compared to 6 disks, I would drop the last $150 and leave it run until it was obsolete, as I don't think I will use 12TB any time soon. My Raid1 array today is 3.7TB formatted with 2TB free...

 

[gpsguy]

I hear you. I *thought* about buying yet another one (already have a 40 & 54) from NewEgg on Black Friday.

But, in the end, decided against it.

It was inexpensive enough that I could flip it back on eBay for near what I paid.

 

[shimian5]

I just meant the RAM. I got the 4GB of ECC for under $40 shipped. 8GB DIMMS are insanely expensive lately, like 30-40% more than I recall paying in the past.

So does anyone have any real world thoughts on a 5 disk vdev for raidz2?

 

[krikboh]

You will see negligible performance impact running 5 disk vs 6 disk.


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