# Raid 5 Upgrades



## Dragoneer (Jun 28, 2006)

http://www.newegg.com/Product/Product.asp?Item=N82E16822148140
http://www.newegg.com/Product/Product.asp?Item=N82E16816116032

Eventually, I' like to upgrade FA to full SATA Raid 5 to ensure full data protection for the site. Been considering investing into the above drives (along with the appropriate chassis). Been debating on what to get for the site. Any opinion on the above?


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## WebsterLeone (Jun 30, 2006)

I haven't done any kind of RAID myself, but I did stay at a Slashdot Inn last night...  So note that everything I say about it is stuff I've seen other people say.

I've heard that the biggest problem with hardware RAID is that if the controller dies, there's a chance you won't get your data back.  Now, if you have backups, that's fine if you don't mind the time it takes to restore everything from backup.  I've also heard that software RAID with a decent controller is not as bad as it seems. On the other hand, if disk performance is a bottle-neck, you might want to look for 10,000RPM drives.  I can't really comment on the specific hardware, but perhaps a bump will turn up someone with a little more experience? :X


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## nrr (Jun 30, 2006)

I was going to post my deepest, darkest thoughts on this here, but I decided that it was more in my interest not to.  Nobody in control of FA's ops has really listened to me on these matters thus far, and I seriously doubt that anyone will any time soon.  I'm frustrated, and I don't think I'm going to eat my wrists up any more for the sake of helping an organization that doesn't want to be helped.

I will part saying only this: RAID is merely a short-term bandage for a long-term problem as far as file servers go.  If the host with RAID goes down, the whole mess goes down.  Plan accordingly down the road.


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## WebsterLeone (Jun 30, 2006)

Indeed, RAID is no means a replacement for a good backup.  All it is meant to do (Except for striping...) is to prevent failure if one or maybe two drives (Depending on the array) die.  I'd suggest checking for RAID controllers that can send out alerts one way or another.  Some have built in ethernet ports for SNMP, but it doesn't help if you don't have a way of receiving those messages.  Some even report back abnormal conditions that are a precursor to the drive failing.


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## Dragoneer (Jun 30, 2006)

nrr said:
			
		

> I was going to post my deepest, darkest thoughts on this here, but I decided that it was more in my interest not to.  Nobody in control of FA's ops has really listened to me on these matters thus far, and I seriously doubt that anyone will any time soon.  I'm frustrated, and I don't think I'm going to eat my wrists up any more for the sake of helping an organization that doesn't want to be helped.
> 
> I will part saying only this: RAID is merely a short-term bandage for a long-term problem as far as file servers go.  If the host with RAID goes down, the whole mess goes down.  Plan accordingly down the road.


That's a good point, actually. That's one of the reasons Tylenol still needs to be build as a remote backup server for FA -- so we have an up-to-date archive in the event of failure.


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## WebsterLeone (Jun 30, 2006)

Even with an up-to-date backup server, it wouldn't hurt to get your hands (tentacles, whatever) on a decent tape drive.  If you have the funds/connections needed to get one, at least. >:X


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## nrr (Jul 1, 2006)

WebsterLeone said:
			
		

> Indeed, RAID is no means a replacement for a good backup.


You missed the point.

There's a lesson I've been trying to teach from day one: CLUSTERING.  Learn it, live it, love it.

There's also a reason why I've been spending a lot of time working on 4c and not, erm, launching it.  Wonder what that reason is?  I'm making sure that it's robust enough to handle having a few nodes on the network go down (or having a few nodes added to the whole scheme for all intents and purposes of growing) and still have everything accessible, as if nothing happened as far as the client is concerned.

_*whistles... o/`*_


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## WebsterLeone (Jul 1, 2006)

I'm suprised that FA has enough for clustering, but okay. :X


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## Dragoneer (Jul 1, 2006)

WebsterLeone said:
			
		

> I'm suprised that FA has enough for clustering, but okay. :X


If somebody wants to toss some Opterons and motherboards our way, I'll be all up for clustering and distributed processing! Anybody have a spare $3,500 so we can grab two more 1U boxes?


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## xsv (Jul 22, 2006)

Dragoneer said:
			
		

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Sure, let me go out to my money tree here...

You want me to fly it to you on my private jet, or should I use the teleporter?


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## blueroo (Nov 4, 2006)

http://www.siliconmechanics.com/i4458/1u-opteron.php

$1044 gets you:

Opteron 146, 2ghz, 1MB cache
1GB (2x512MB) PC3200/DDR Unbuffered ECC
3Ware 8006-2 2 port SATA RAID controller
2 Western Digital 160GB 7.2k SATA Drives

That's a fast but cheap webserver/database server, and gets you warranty replacement as well. Run Raid 1 for minimal redundancy and speed. Raid 5 will eat an entire disk for parity and has a minimum requirement of 3 disks, driving up the cost of your servers. The 3ware will give you messages when there are problems with the array, and supports standard features like rebuilding your array and operating in a degraded state. Combined with SMART, you should have reasonable forcasting for disk failures.


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## Dragoneer (Nov 4, 2006)

blueroo said:
			
		

> That's a fast but cheap webserver/database server, and gets you warranty replacement as well. Run Raid 1 for minimal redundancy and speed. Raid 5 will eat an entire disk for parity and has a minimum requirement of 3 disks, driving up the cost of your servers. The 3ware will give you messages when there are problems with the array, and supports standard features like rebuilding your array and operating in a degraded state. Combined with SMART, you should have reasonable forcasting for disk failures.


We decided to go with RAID 1+0 plus a fifth drive for a full additional backup (or storage for large files).

Raid 1+0 will offer a speed advantage along with the new RAID controller we're buying.


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## blueroo (Nov 4, 2006)

Dragoneer said:
			
		

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That's exactly what I would use for a read heavy database like FA has if the budget was available.


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## Dragoneer (Nov 4, 2006)

blueroo said:
			
		

> That's exactly what I would use for a read heavy database like FA has if the budget was available.


The upgrade will probably happen by the end of the year. We'll also review the server and see if anything else needs an upgrade.


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## blueroo (Nov 4, 2006)

Dragoneer said:
			
		

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If you need another admin's eyes, I'm always available. Sairah wants me to spend less time in my office, but eh.


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## blueroo (Nov 4, 2006)

BTW, have you ever considered using mod_gzip and a php cacher to reduce bandwidth usage and increase site responsiveness?


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## Dragoneer (Nov 5, 2006)

blueroo said:
			
		

> BTW, have you ever considered using mod_gzip and a php cacher to reduce bandwidth usage and increase site responsiveness?


What, efficiency? You realize, sir, that this is FA!


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## Kougar (Nov 5, 2006)

Very glad to hear y'all are switching to a RAID set up, I was wondering about that after I read through http://www.anandtech.com/IT/showdoc.aspx?i=2859 Even 15krpm drives can be brought down to a few MB/s crawl if the I/O or request load is saturated enough. I'm sure FA about generates those kinds of loads already for basic drives.

I bought four of those exact Seagate drives when prices dipped, planned for a RAID 5 that never materialized because this mid-range board doesn't support it and I never carried through with my plan to upgrade mainboards. So far they are very nice drives nonetheless. Word of warning though, I also got them from newegg and two of the four drives were from China and have an older firmware on them, while two were from Singapore or Malaysia with newer firmware. This shouldn't pose any issues as far as I know, but it's something to stay aware of. These desktop drives are not optimized for database hosting though... Seagate does offer "Nearline" (NL 35 series) SATA drives that have a slightly higher reliability/durability built into them, besides being built for the enterprise/database workload.


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## CyberFoxx (Nov 5, 2006)

Well, all I can say is make sure you are doing hardware RAID, and not software RAID. And make sure it's a decent hardware RAID controller too. Good way to check if it's a good RAID controller, it has a battery.

Why Software RAID is bad? Well, it's not, I got a RAID1 setup in my home server for /home and it works just fine. Just that if one drive does fail, the IDE controller will disconnect that IDE channel. It's a built-in safety measure. A good Hardware RAID controller will just unmap that dead drive and the second will still work. Now, I don't know if it's the same with SATA, haven't even touched a SATA drive yet, but it does support Daisy-chaining drives still, doesn't it? Well, the first edition of the draft for SATA said it did, never heard anything about it since...

The battery is mostly used for backing up of the partition tables and RAID drive mappings. This is just in case the power fails, the card won't "forget" how the array was setup. Trust me, I've heard stories of cheap RAID controllers forgetting they even had an array to begin with after power was restored.

And let me repeat what has already been said, RAID is no replacement for a good backup strategy. All RAID is, is just a tiny bit of extra insurance, that's all. RAID won't protect you if the place where the server is hosted burns to the ground, but having tape backups mailed to your house will. (Yes, some hosting companies will UPS tape backups to you.)


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## Kougar (Nov 5, 2006)

None of the official I, II, or 2.5 specs allow SATA drives to be daisy-chained, unfortunately. But I don't miss the master/slave headaches that come with that ability. 

Going back to the first post it's a given it will be a hardware RAID. I don't know anything about that PCI-X card, but 128mb of cache is a good plus, and it seems to support most RAID formats, the only glaring exception appearing to be RAID 0+1. PCIe 4x or 8x might be better, but that depends on the motherboard the RAID card is getting plugged into more than anything else.


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## goat (Nov 6, 2006)

i have that exact same hard drive as my primary...... pretty ol' slick if i do say so


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## CyberFoxx (Nov 7, 2006)

Kougar said:
			
		

> None of the official I, II, or 2.5 specs allow SATA drives to be daisy-chained, unfortunately. But I don't miss the master/slave headaches that come with that ability.



Dang, really? I heard it was supposed to be self-terminating. Kinda like SCSI, but the drives would auto-detect if there was a drive after it, thus you didn't have to manually add a terminator. That way you avoid that Master/Slave stuff. Oh well, maybe they had problems implementing it and might be waiting for a later revision, who knows. Would be nice if they did add it, for those of us who foolishly got a mini-ATX board and are already using up both the two PCI slots they get. ^_^

Anyway, finally got around to actually checking out that SATA RAID controller you guys are thinking about getting for the site, it's quite nice. One feature that you don't see much of is the SNMP support, it can be quite handy. Can't find any info that says that specific model supports battery backup.

From what I can tell from my little dabbling with RAID, that does look like a good controller card.


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## Kougar (Nov 7, 2006)

Yep, SATA is a serial point-to-point design, it wasn't built with the ability/protocols to host multiple drives off the same port, which saves overhead. Hate to kill your hopes, but if they did add that ability it would require entirely new hardware in the drive controllers (IE controlling chipset or SATA card) to support any of it.

You're right that there is no battery backup option, didn't see a button cell on the card itself in the NewEgg pics.  As long as the system is running off of a backUPS unit I don't think it's a critical feature though... anyone using a computer with relatively recent hardware should already be using one as they're cheap enough and very useful to have. Especially with US grids in the condition they're in.


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## Kougar (Nov 12, 2006)

Ran across this again, and to my surprise it happens to feature the exact 3ware RAID card that you were looking at. Might be worth a read... http://www.tomshardware.com/2005/10/31/sata_spells_trouble_for_scsi_raid/index.html


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## Dragoneer (Nov 12, 2006)

Actually, right now we've been discussing things. We're going to do RAID 10 most likely. We're also debating upgrading the server to something a bit more long term.


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## Kougar (Nov 12, 2006)

I'm reading, I'm reading.... forgot what RAID 10 even is! Will post in the new thread after I can at least get an idea together.  Whomever had the RAID 10 idea, it's a good one to keep!


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## Dragoneer (Nov 12, 2006)

Kougar said:
			
		

> I'm reading, I'm reading.... forgot what RAID 10 even is! Will post in the new thread after I can at least get an idea together.  Whomever had the RAID 10 idea, it's a good one to keep!



RAID 10 is also known as RAID 1+0.

Essentially, you take have (for example) four drives, and you put two each into mirror. Then, you take both sets of mirrored drives and put them into striping, so you get the full benefits of mirrors AND the speed bonus.

Due this eight smaller drives (e.g. 160GB drives) and fire for hyperspeed effect.


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