Need Raid 5 Suggestions / Help

[infiniti_guy]

What happens if I change from Win to Linux down the road, if I have the Escalade 9500 card running? Do I loose everything? Do those cards work with Linux?

[infiniti_guy]

Whoa! That Escalade 9500S-8 card is $$$ expensive! Is there anything a little less expensive that will work well?

[mdmint]

Originally Posted by infiniti_guy

Thanks for the info.

I was only thinking about AMD64 because I want my server to manage Sage (w/out Client functions), all my files, etc. And I want it to last a long time 5-7 years (just doing those functions). So I was worried about that...

BTW an AMD64 2800 chip OEM runs $112 these days. Whereas a Sempron 2600 OEM will run $70. But money is money.. If I won't need it to expand my server over the years... I'm all for saving money.

Hmmm, 5-7 years is a LOOOooonnng time in the computer world! Even though file serving isn't that CPU intensive if you can afford to go the AMD64 what the heck. If you do go with that mobo I'd highly suggest a large server case that'll hold LOTS of hard drives. That way you could always add another RAID controller later for a second RAID5 array when (most likely not if) more storage space is needed in the future. Then again could always add external or networked storage. So many options! I went with a mini server case and it's totally maxed out with 8x250 SATA HDs, CD and single PATA HD (PATA used for OS Ghost/backup boot HD, config'd RAID5 with 5GB boot partition, rest 64k striped storage partition) I kind of now wish I'd gone a larger case. My only option storage expansion option now is external, currently transitioning using 500GB of my main workstation 4x250 RAID5 for Sage Library networked storage. But that's a system I'm always fooling around with so not the ideal for "always available" storage. Having had my Sage setup since May 04 if I had to do it again I'd likely do the Server a bit different. Heck, initially I'd planned a 4x250 RAID5 but very soon realized it wasn't going to cut it. That's how the Promise FastTrak S150 SX4 w/256MB cache ended in my workstation, upgraded the Sage Server to Escalade 9500S-8 w/256MB cache a couple months after initially putting Sage into service. (Though I already had an Adaptec 2400A 4 port 32MB cache PATA RAID5 controller in my workstation, it's now in Debi's PC just running a RAID1... )

If you're thinking about uptime for the Server have you thought about dual redundant hotswap power supplies? They're made in PS2 form factor now. I'm using an I-Star 2x400w. Took a wee bit of case modding/cutting to get it to really fit, but not much. They also make 2x500 & 300 models. And I really don't regret using hotswap drive cages now that I'll be replacing all 8 of the HDs in the Server, doing it live online, one at a time. (Replacing the standard Western Digital SATA WD2500JD with Raid Edition WD2500SD at no additional expense. First 5 RMA cross shipped ETA Tuesday.) And don't forgot mungo UPS! (I'm good for 90+ minutes no power to house all HDs hammering away, APC 1500 w/2nd slave battery. )

BTW, have you started planning your Quiet HTPC Client yet? Upgrades to mine on the way, you may REeAalLy want to check out the Mcubed T-Balancer amoung other things! Oh heck, just give me your credit card and I'll buy you all kinds of cool stuff!

[mdmint]

Originally Posted by infiniti_guy

What happens if I change from Win to Linux down the road, if I have the Escalade 9500 card running? Do I loose everything? Do those cards work with Linux?

Yes, Red Hat & SuSE Linux driver supported.

Originally Posted by infiniti_guy

Whoa! That Escalade 9500S-8 card is $$$ expensive! Is there anything a little less expensive that will work well?

Good solid hardware RAID5 has never been "cheap". Though Promise, Escalade & Adaptec all have PATA & SATA solutions much more affordable than SCSI. What will do larger than 4 drive RAID for less $$$? Guess that's were the Linux software RAID solution guys come in... You gotta pay to play! Or why so many people just use JBOD

[stanger89]

Originally Posted by infiniti_guy

What happens if I change from Win to Linux down the road, if I have the Escalade 9500 card running? Do I loose everything? Do those cards work with Linux?

Drivers are easy, it's the filesystem that's tricky. Windows doesn't support Linux EXT3. I haven't investigated much lately, but it may be possible to convert NTFS to EXT3. Also, FWIW, linux can read NTFS, but I don't think it can write to it, and if it can, I wouldn't trust it yet.

IMO, if you want to go linux eventually, do so now, build your server, set up your filesystems, and if necessary run Sage on a Windows PC until you are able to switch.

Speaking of speaking, can you share any info you got from Jeff or Dan? I'm rather curious, we here on the forums haven't heard much from them since CES started. Not surprising, I'm guessing they're really busy there.

Oh, and if you're planning on a 5-7year server, there's no controller I'd go with over the 9500s. Something like that is not something I'd cut corners on.

[infiniti_guy]

On the CES side, yes I can share, especially since I've seen you guys share so much on the forums. Sage is moving to Linux soon (early 2005). They will continue to support windows, but they are very interested in Linux for performance, stability, and cost. I saw their system, and they had a prototype running at the show. It was getting feed from their new Linux box (displayed in a Silverstone LC11 case). They also had another display using the Media MVP as a client running on another screen.

On this forum, the main implication is Linux. I would both plan and anticipate the Linux conversion for high-end servers because this makes a lot of sense. I believe most of this is public information (see the Sage Announcements forum for more info).

[stanger89]

I believe most of the Linux uncertainty revolves around just where Linux support is going, ie if it will be OEM only for integrated box, or if it will be a new consumer version parallel to the Windows version.

[mdmint]

Originally Posted by stanger89

Oh, and if you're planning on a 5-7year server, there's no controller I'd go with over the 9500s. Something like that is not something I'd cut corners on.

I agree not to cut corners on a RAID controller. I own and use a 9500S-8 in my Sage Server. As far as control of the HD RAID and RAID performance it does well. That said it has definite limitations compared to both Adaptec & Promise SATA RAID controllers. Feature set wise Adaptec & Promise both outstrip 3Ware solutions. Both Adaptec & Promise support RAID Level Migration, 3Ware does not. What's that you say? The ability to change RAID level or "type" on the fly maintaining data. Works marvelously with the Promise FastTrak S150 SX4, I haven't had the opportunity to see it in action with Adaptec. Specifically initially setup my main workstation with SX4 and two HDs RAID1. A few weeks later added a third HD and "Migrated" from RAID1 to RAID5 with PC still fully functional the whole time. I've spoken with 3Ware tech support a number of times and it's not in the works. Next is Online Capacity Expansion, the ability to add additional HDs to existing RAID5 and make it bigger. I have a 4th HD coming for my workstation which I'll just slide in (have hotswap bays) and expand the RAID5 from 3 to 4 drive array live time. Adaptec supports this also. When I bought the 9500 six months ago it was advertised as OCE "ready". At that time projected implementation was Nov or Dec 04. I talked to 3ware tech support again just last week, they have no idea when it'll actually happen. Likely because 3ware got et up by AMCC. Their adverstising still says OCE ready. Ready but not implemented with no ETA. What does this really mean to the user. Migration & expansion capabilities mean you have room to grow your system without having to figure out how to dump huge amounts of data to other storage, reconfig RAID adding HDs to make it bigger, and put data back. Most of us won't likely have an EXTRA TB(s) or so storage to do this. Lastly the big hit on 3ware is back in the Spring when I purchased they advertised monitoring support for their drive cages coming in the fall. (Cage temp, fan speed etc.) Hasn't happened and again tech support has no idea when or if it will happen. What this means is 3ware solution doesn't even monitor THEIR drive cages so I don't know the drive temps or condition of their 6 fans, no alarms etc if too hot or fan fails. Both Adaptec & Promise have active monitoring of their enclosures. I know the temps & fan condition of my 4 Promise cages. SX4 will let me know if something goes wrong. One other hit against the 3ware is drive compatibility. Specifically Western Digital standard JD series SATA drives ALMOST work with the 3ware (though their tech support says they shouldn't be a problem). Testing and talks with WD confirm the problem. Under very heavy data writes the JD drives can AND DO time out causing delayed write failure. The same does not happen with the exact same JD drives and the Promise S150 SX4. I don't know about how the same JDs work with the new Adaptec SATA controllers, only have an Adaptec 2400A PATA. (Fortunately for me Western D once again comes through with excellent service and is replacing my JD drives with more expensice SD drives at no charge.)

Bottom line until AMCC decides to live up to the promises and plans made by 3ware before AMCC bought 3ware I'd be leary. It really does suck not be able to monitor the 3ware expensixe hotswap cages. If I'd known 3ware was renigging (or rather new parent AMCC renigging) I'd likely have sprung more $$$ and gone Adaptec. Though I do like 3ware web based monitoring interface over Adaptec's or Promise's programs. Just the darn monitoring doesn't monitor their cages... Yeah, it ticks me off. I even had to build my own wiring for the cage lights to work. Weak. Hopefully someone's still around their high enough up the food chain from before the AMCC takeover who'll keep good on former 3ware promises.

I won't get into the number HDs supported per card and reasoning behind Promise's only 4 drive card while 3ware has a 12 and Adaptec a 16. Promise actually has sound reason, mostly from a business and for businesses standpoints.

[infiniti_guy]

Originally Posted by stanger89

I believe most of the Linux uncertainty revolves around just where Linux support is going, ie if it will be OEM only for integrated box, or if it will be a new consumer version parallel to the Windows version.

I don't know the answer to that one, sorry. I think you will have to ask Sage.

[mdmint]

Originally Posted by mdmint

Bottom line until AMCC decides to live up to the promises and plans made by 3ware before AMCC bought 3ware I'd be leary.

I should qualify that. If you're going with 3ware 9500 series and maxing out HDs initially them not supporting RAID Migration & Expansion is a non issue. If you don't plan on using their hotswap drive enclosures the fact that they aren't monitored is also a non issue, 3ware does monitor the drives themselves fine, just not their cage enviroment. Lastly even if you go with Western Digital's JD series SATA drives if you NEVER write multi-gig files to the array they're fine. (I don't mean multi-gig files being recorded, they take time to "build" and are handled no problem, I mean mult-gig file transfers to the array from another array of file(s))

[stanger89]

mdmint,

A little OT, but you're running a notebook drive in your client right? Where'd you get the laptop -> normal IDE adapter?

[infiniti_guy]

I would like to add to storage capacity as I go. That I think is important. Personally, I thinik 2 TB (8 drives) would be plenty to last a few years (for me). But in a few years, I might want to be able to expand to anbother array of 2+TB.

Someone suggested only 6 drives on a RAID 5 array, should I stick with that or can a put 8 and still get good performance?

Please correct me if I am wrong, but my understanding is that with 8 300GB drives, I can get 2.1TB (7 with usable data). How hard is it to recover data if a drive fails, I read it could be a little tricky w/RAID5?

And will a PCI bus be sufficient for 2 2TB arrays (down the road), or should I look at PCI-E?

[stanger89]

Originally Posted by infiniti_guy

I would like to add to storage capacity as I go. That I think is important. Personally, I thinik 2 TB (8 drives) would be plenty to last a few years (for me). But in a few years, I might want to be able to expand to anbother array of 2+TB.

Someone suggested only 6 drives on a RAID 5 array, should I stick with that or can a put 8 and still get good performance?

Theoretically performance will increase as you increase the number of drives. FWIW, my array (8 WD2500JBs on a 7506-8) can read about 90-100MB/sec (PCI bus can't do much more than that), and write at about 40-50MB/sec.

What I would look at when deciding how many drives is $/GB, and remember to consider everything.

Please correct me if I am wrong, but my understanding is that with 8 300GB drives, I can get 2.1TB (7 with usable data). How hard is it to recover data if a drive fails, I read it could be a little tricky w/RAID5?

Basically, but it's a little tricky since HDD manufacturers measure space in base-10, while the OS calculates it base-2. For example my array is 8x250 or 1.75TB for RAID-5, however the actuall space comes out to be a little over 1.6TB.

Although I haven't had a drive fail (yet) it's not difficult with RAID-5. Basically you just replace the bad drive and tell the array to rebuild, there's no "recovery" since no data is lost. It will take a while to rebuild though.

And will a PCI bus be sufficient for 2 2TB arrays (down the road), or should I look at PCI-E?

Capacity doesn't have any bearing on buss type. The only thing you'll loose going normal PCI is a little read speed, for example it's possible to pull several hundred MB/sec off these cards, but normal 32/33 PCI will limit you to about 100MB/sec. To get more you'd need to go PCI64 or PCI-X (64bit/133MHz PCI, not the same a PCI-Express/PCI-E/PCIe). For a media server you won't need the extra bandwidth so I'd say normal PCI is fine.

[mdmint]

Originally Posted by stanger89

mdmint,

A little OT, but you're running a notebook drive in your client right? Where'd you get the laptop -> normal IDE adapter?

Well, you "could" use laptop drives in an array! Couldn't find the email or paperwork for the one I got in May. I just got a second conversion kit last week, this one from a regular eBay seller store, he beat best Pricewatch. http://stores.ebay.com/Cablesforpc_A...isplayZ2QQtZkm
Kit w/ interface & power adapter & 5&1/4" mount & screws $7.49 total inc. s/h. Fast shipping.

[mdmint]

Calculating storage capacity of a RAID5 array quite simple formula: (X-1)Y
X=number of drives
Y=drive capacity
With online spare it's: (X-2)Y, my 8 HD RAID5 config.

The "RAID5 6 drive design limit" is guideline. IRRC one main reason is your risk of single drive failure is multiplied by number of drives. In other words with an 8 drive array you're 8 times more likely to have a drive fail than with a single drive. But of course with RAID5 data would not be lost, would continue to run in reduced performance no longer redundant recreating data via Parity. Replace drive and rebuild, data redundancy back. However, if a 2nd drive fails before 1st failed drive replaced or during rebuild your data is toast. Which is why I built mine with online sparre, if a drive fails array will immediately begin rebuild not needing failed drive replaced first. Which is also why NEVER use RAID0 for anything with data you care about! (RAID0 fastest performance yes and but most likely to fail of any HD configuration)

Even better than RAID5 with online spare is what is sometimes called RAID6. It's like RAID5 except using double parity meaning you can loose two drives simultaneously without loosing data. Same storage formula capacity as RAID5 with online spare but safer. And can still have online spare: then it's (X-3)Y. Unfortunately I've only seen it on some high end SCSI RAID controllers, no SATA or PATA or I'd be using RAID6 instead of RAID5 with online spare.

[infiniti_guy]

Ok, what if I decide to run the client on the Sage server with the RAID5 config. E.g I want to use a few Media MVPs running off the Server.

Then, I would need the extra CPU power correct, to manage all the traffic (file Server), and send the display to the MVPs. Then, maybe, I am talking about the AMD64 processor?

Or is this a bad idea to mix the file server (w/RAID5) and the MVP display? E.g. would the multiple running Clients cause performance problems with the RAID?

[infiniti_guy]

And for a final decision on the RAID5 Card...

1) If I want to add to the size of the array over time, run say 8 drives, which card should I get (I heard that the 9500 doesn't have the OCE working yet)? Price is a big issue for me.. but the ability to use this card long term is also important.

2) Can I buy a second RAID Card in a couple years and double the array size?

[mdmint]

Originally Posted by infiniti_guy

Ok, what if I decide to run the client on the Sage server with the RAID5 config. E.g I want to use a few Media MVPs running off the Server.

Then, I would need the extra CPU power correct, to manage all the traffic (file Server), and send the display to the MVPs. Then, maybe, I am talking about the AMD64 processor?

Don't know for sure if you would need that much cpu power but it definitely wouldn't hurt.

Or is this a bad idea to mix the file server (w/RAID5) and the MVP display? E.g. would the multiple running Clients cause performance problems with the RAID?

I doubt it'd be a problem as far as the RAID5 performing.

And for a final decision on the RAID5 Card...

1) If I want to add to the size of the array over time, run say 8 drives, which card should I get (I heard that the 9500 doesn't have the OCE working yet)? Price is a big issue for me.. but the ability to use this card long term is also important.

Correct, 9500 series does not have OCE implemented and their tech support has no idea when or if for sure it will happen per my phone conversations with them last week. If you want OCE capability assured with 8 (or more) SATA HDs right now Adaptec is the only internal solution I know of. Promise has external SATA enclosures with controller in the enclosure that interface via SCSI that'll do it too, very very scalable (which of course means mo' money).

2) Can I buy a second RAID Card in a couple years and double the array size?

Assuming you have slot available (mine full of PVRs) you can add another RAID controller but not expand existing array, you'd need to create another array. IRRC none of the SATA RAID controllers we're discussing support controller spanning. I know I asked one or two of them about it, or maybe it was all three. (When thinking about a super fast RAID10 across two controllers for both HD and controller redundancy)

[infiniti_guy]

So which adaptec card would you recommend?

And are there any negatives associated with using 2 arrays as opposed to one?

[infiniti_guy]

It looks like the 2810SA would be the card for the 8 SATA ports.