The FreeNAS community really shows just how important it is to avoid products like FreeNAS. It's built on good tech, but the issues are that the community is horrible, only tiny non-storage expert shops use it and it is broadly misunderstood. FreeNAS doesn't make any of the technology, they just repackage it. So the vendor and their community all lack the basic knowledge of what they have and the stuff that they repeat just gets worse and worse.

If this was the FreeBSD community, talking about the same technologies, the answers and approaches would be completely different. Enterprises use FreeBSD every day. They do not use FreeNAS. Once you limit yourself to a "non-expert" product, the idea of using a community for assistance causes a breakdown in dangerous ways.

@MattSpeller said:

Learned a lot about RAID from you, it's been fun to learn! Now can you teach me how to get a job as a hardware monkey? 😄

Grab a sledge hammer

@thecreativeone91 said:

Seems appropriate

Youtube Video

Looks like a lot of fun!

For comparison, "cheap" sandisk 256gb SSD in my work laptop:

upload-46cb10a5-1af4-44d0-b0d4-e02ff3e04cd1

http://community.spiceworks.com/topic/1122819-perform-ssd-over-provisioning-optimization-on-the-array-good-or-bad

This should help.

http://www.techotopia.com/index.php/Creating_and_Managing_Windows_Server_2008_Mirrored_(RAID_1)_Volumes

@GUIn00b said in Practical RAID Decision Making:

I guess it would have to be a very specific concern to opt for the parity overhead in favor of the "added protection" over a statistically very rare potential failure scenario of 4-drive RAID-10.

It's a specific failure scenario that even when it happens, there's no way to know if the same scenario would have been protected under RAID 6 because most scenarios where RAID 10 would fail, RAID 6 would also fail during its recovery mode (nearly 100%.) But the chances that it would face that recovery scenario are higher.

The complexity comes from choosing single unpredictable failure scenarios. After a failure has occurred, if we had the ability to pick how to have protected against it in the past, yes, RAID 6 would be chosen sometimes. There's a known example to explain why you can't use this in real life. It's the seatbelt problem.

Seatbelts save lives. On average, by far, wearing a seatbelt protects you. But there are special cases where the seatbelt can be what causes you to die. Yet statically, you never skip wearing a seatbelt because it is a one in a million chance that the seatbelt will cause a death rather than preventing one. And at the time that you choose to wear or not to sear wear your seatbelt you have no idea which type of accident you will have.

So we know that wearing the seatbelt is the safer bet. Seatbelts are like RAID 10. You can't know how things will go wrong, and in this scenario, RAID 10 protects you much more often than RAID 6 does.

Timely article, thanks.

@thecreativeone91 said:

I knew a DBA who we had to teach how to save a word document while she worked with us on some stuff.. and she was also the Database & Programming (C++, VB.NET, Java) professor at a local college

Sounds like someone who failed upwards into that position of DBA

Another factor that people forget with FakeRAID until it is too late... if your OS crashes your RAID is useless. With hardware RAID you can rebuild your RAID after a drive loss even when the system is offline. The datacenter people don't need to know if the OS is healthy, if it is on, etc. They can swap drives and let the RAID controller repair the array.

With FakeRAID there is no RAID until the OS works and is healthy. So even if you replace a drive, the array might be unable to repair itself.

Dealing with someone facing this problem right now. System crashed with the RAID array lost a drive and won't boot. Not the OS is having issues and there is no RAID at all.

We got retweeted by Storage Switzerland too!!

@Texkonc said:

That is like saying Raid is a type of backup..... 😄
Sorry that I am late to the party, my bus broke down.

Whoa, Tex is here!

@creayt said in Testing the Limits of the Dell H710 RAID Controller with SSD:

Link seems to not work.

A bit of necromancy there. . .

It's RAID 100. See the post directly above yours 🙂

Make sure that you post back here when you learn more. Everyone is, I imagine, pretty interested in this one.

If you combine the drive failure rate calculator for RAID 0 with the URE Risk of the RAID 5 calculator you can actually get some decent idea of total risk.

http://www.raid-failure.com/raid0-failure.aspx

@alexntg said:

it would be a "dream job" for a storage-inclined IT professional.

@ScottLongHDS Welcome!

I don't want to shame the vendor, it was just a shocking admission for a vendor to post.