NAS/Storage Megathread: What is this "File Deletion" You Speak of

The Something Awful Forums > Discussion > Serious Hardware/Software Crap > NAS/Storage Megathread: What is this "File Deletion" You Speak of

cypherks: Apr 9, 2003

Not sure if it's the right thread, but I can answer any questions about EMC Clariion and Celerra, iSCSI and Fiber Channel switching. I've done a bunch of SAN with ESX 3.0 and 3.5 installs as well.

# ¿ Mar 22, 2008 01:11

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# ¿ May 3, 2024 18:00

cypherks: Apr 9, 2003

teamdest posted:

well then I'll take you up on that: could you give a basic overview of what a SAN is, how it is hooked up/accessed, etc? I've got my NAS and was thinking of building a SAN and realized I literally know nothing about them, and even iSCSI confuses me when I try to figure out what's going on. I believe I just fundamentally don't understand what a SAN is for.

With a SAN, you can pick and choose your disks, and LUN sizes. Say you've got a tray of 15 disks. You can do RAID 1, 3, 5, 10, or 6. Once you have a RAID group, you can carve out LUNs. Let's say you have 3, 500GB disks. Put those in a single RAID 5 group. Out of that you could carve out, for example, 10, 300mb LUNs. Present those LUNs to servers, and what they'll see is the 300mb of storage.

Basically what a SAN does is manage storage for hosts. There's a lot of smoke and mirrors but what you end up with is a host that thinks it has local storage, when in fact it resides elsewhere.

iSCSI - all you're doing is using an IP network to transport SCSI commands. You set up storage on the SAN, give it an iSCSI IP address and pick what host/server you'll send it to. On the host/server, you set up an iSCSI initiator, point it at the SAN and voila, you have storage.

Let me know if you want more info or details, I'm keeping it pretty simple.

There is a ton of info available at http://www.snia.org/home - it's vendor neutral.

If anyone really wants to mess around, there is a SAN simulator, free, available from EMC. Not sure what the rules about 'filez' are these days otherwise I'd put up a link.

# ¿ Mar 22, 2008 21:47

cypherks: Apr 9, 2003

It's been a long time since I posted in this thread; thought I'd try to jump back in.

I can answer questions about most EMC products, although my focus is on Clariion and Avamar. I know a decent amount about fiber-channel switches and iSCSI as well.

At home I'm in the process of putting together a 15TB NAS running off Ubuntu or FreeNAS, haven't decided yet. I'm waiting for 1.5TB disks to drop below $100.

# ¿ Jul 3, 2009 05:26

cypherks: Apr 9, 2003

complex posted:

We have a Clariion. Have you ever dealt with Solaris' native IO multipathing? The manual seems to hint that Solaris can't deal with third party arrays that are active/passive, or at least that it's not supported.

Yep, I've seen this before. You need to get a copy of Powerpath. The free version will do path fail-over while the paid version will do both load balancing and fail-over. I think the list price for what you need is about $800. If you want to test it, you should be able to google an activation code.

# ¿ Jul 3, 2009 16:19

cypherks: Apr 9, 2003

Interlude posted:

Got my ubuntu server box raid5 going, loving it thus far. Toyed with freeNAS and liked it a lot but thought it was a bit crippled in terms of ability to add more advanced services. EG there's a 3rd party slimserver plugin but it's not updated to use the latest freeNAS version yet and the guy's website says "yeah too busy right now, try again later".

What do you guys use for backup software? I was toying with the vista built-in crap but it's just not configurable enough. Basically my main goal is to do daily mirrors of my photos to the server (and I say mirror because I want it to maintain directory structure, etc., not try to .zip up my JPGs and back them up in a new format like the vista util does).

How many disks do you have in your R5 setup? I'm confused as to why you'd run backups against an R5 array...

# ¿ Jul 7, 2009 00:57

cypherks: Apr 9, 2003

adorai posted:

I can't tell if you are trolling or not, I'll assume you aren't.

Granted, this thread is oriented more toward personal storage, however, I can think of a number of reasons to backup a raid 5 array. Here are a few:

1) multiple drive failure
2) array corruption due to controller failure
3) recovery against accidental deletion
4) regulatory requirements (must keep data X number of years)

There are a lot more, less common reasons.

No, I'm totally not trolling. I was just thinking of my own home array, which will have 10 disks in it when done. I just don't see the need for backing it up. The odds of having 2 disks go bad at the same time, or two before I can fix one, I think are pretty darn low.

Now, something at work, of course, there are lots of reasons, such as what you mentioned above. I guess I should have asked "Why are you backing up your home R5 array". I'm just curious.

# ¿ Jul 7, 2009 04:26

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# ¿ May 3, 2024 18:00

cypherks: Apr 9, 2003

Interlude posted:

Not backing up the array, I'm talking about backing up TO the array from a Vista box.

Then I am a tard who can't read. Sheesh!

# ¿ Jul 7, 2009 05:55

The Something Awful Forums > Discussion > Serious Hardware/Software Crap > NAS/Storage Megathread: What is this "File Deletion" You Speak of