Need Raid 5 Suggestions / Help

[mdmint]

Originally Posted by edbmdave

Can someone explain to me why having the SageTV server running on a machine with a raid5 for its storage is bad?

It's not bad. It's quite excellent. I built my SageServer last May with 8 250G Sata HDs RAID5 controlled with 3ware 9500S-8, AMD XP2100+ (2100+ more than needed but laying around), 512M, 4 PVR250s in Server (before the 500s came out) plus 1 PVR250 in main HTPC Client Network Mode. Rock solid. No problem recording 5 concurrent DVD Standard Q recordings while also streaming 3 previously recorded to Clients AND running Comskip on the Clients all at the same time. This talk of RAID CTRLR and the PCI bus not being able to keep up is just that, unsubstantiated talk. The Server was solid from day one on v2 and is still solid V2.1.10 in Service Mode. However, I do not use the Server as a Client so likely aids in it's stability. I built it to be a dedicated stable Sage Server and that's what it is. Oh, an advantage of having the RAID array IN the Sage Server is being able to hibernate the Server and turn off the HDs when not needed with v2.1.10. Never missed a recording from not waking up. If Server asleep and you want to access it just ping it from a Client to wake it up. I put Ping routine in Startup of main HTPC Client plus PingSageServer icons on desktops of all Clients. It be cool.

Planning on attaching a cheapo modem so can wakeup on modem ring if asleep for remote Web access.

I can't see that it would be a big difference this way verses having the network IO + clients connecting if I was connecting to the RAID5 as a shared volume elsewhere. It would seem to be better to allow the server to write natively to the raid 5 array verses over a network. I would also thiink this would aid in support a larger number of concurrent recordings. I was thinking I would have a box with 2 PVR-500s and 1 PVR-250 (So 5 concurrent). The 500s would record anything from standard cable, the 250 would be tied to a digital cable box and record the digital channels via SVideo. All on a machine with 1GB Ram, and a AMD 2600. I would think this would be a good thing.
Thoughts??

If it's to be a dedicated Sage Server you don't need a Gig of RAM and AMD 2600 way more than enough CPU.

On the other hand a gigabit connection to NAS from Server wouldn't have any problem keeping up with 5 or 10 concurrent recordings either.

[mikesm]

Originally Posted by cnovak

Never ever ever go software RAID. You're better off without protection at all than going software RAID IMHO. I know that sounds funny, but I've personally run into a lot of issues using s/w RAID.

Cory

I think this is an overly broad statement. I wouldn't run software RAID in windows for a variety of reasons, but Linux software RAID support, particularly RAID5 is quite good, high performance, and much more flexible than any hardware raid solution I have used.

As I said however, if you aren't a Linux user, I would stay away from it. It's way easier to administer than it used to be, but still I would stay away form it if I haven't run Linux before.

What issues have you had with Linux software RAID?

Thanks,
Mike

[mikesm]

mdmint, running Sage server and the filestore on the same system is fine if you aren't sticking it in the living room, as lots of disk makes heat and noise that can be irritrating.

That said, powering down disks means the data isn't available from other systems with going through WOL and taking a latency hit. Coming up from standby will take awhile as you want to spin the disks up one at a time to avoid a power spike when they all start at the same time. If you have a lot of disks it could pull the 12V rails below what the system needs to stay up.

But if it works for you, that's great...

Thanks,
Mike

[mdmint]

Originally Posted by mikesm

mdmint, running Sage server and the filestore on the same system is fine if you aren't sticking it in the living room, as lots of disk makes heat and noise that can be irritrating.

Duh, that's why I call mine a "Server". Servers are traditionally off out of sight out of mind as far as the end user is concerned. In this case, the end user being main HTPC Client plus a couple other PCs with Client.

That said, powering down disks means the data isn't available from other systems with going through WOL and taking a latency hit. Coming up from standby will take awhile as you want to spin the disks up one at a time to avoid a power spike when they all start at the same time. If you have a lot of disks it could pull the 12V rails below what the system needs to stay up.

What's to go through using wake on lan? I added pinging the Server IP in my main HTPC startup so it's automatic plus made ICONS to wake up server on other PCs with Client. BTW, I just timed bringing my Sage Server out of hibernation to ready, all of 57sec. (I do mean hibernation, not standby, total POST with WinXP resume boot.)


I'll have to say duh again you want to avoid power surge, basic HD array design implimentation, been working on Backoffice equipment for 20+ years. However, even with my 8 250G HDs staggered at 1sec powerup intervals that only means 8 additional seconds to come out of hibernation.
On a software RAID note: how do you implement hardware staggered HD spinup? Don't see how you can. I'll stick with hardware based RAID thank you very much.

But if it works for you, that's great...
Thanks,
Mike

And if software RAID works for you, that's great too...

On the other hand I agree with someone else's statement about possible negative "side effects" of powering up and down alot. My experience tends to agree the greatest risk of failure is at powerup. So it's a trade off between saving power with hibernation since Sage Server primarily used in the evenings versus leaving on 24x7 which I did until v2.1.10. Using hibernation and automating bringing the Server out of hibernation with a high WAF factor has mostly been an exercise in getting it to work seamlessly. I've yet to decide if I'll use hibernation on the Server long term...

[mdmint]

Originally Posted by mikesm

I think this is an overly broad statement. I wouldn't run software RAID in windows for a variety of reasons, but Linux software RAID support, particularly RAID5 is quite good, high performance, and much more flexible than any hardware raid solution I have used.
Mike

I'm curious, in what way is Linux RAID more flexible than decent hardware based RAID? (Other than the drives being physically connected to the controller in hardware based RAID)

[mikesm]

MDmint, staggered power up is a function of the controller the drives are plugged in to. The latest SATA drives have an explicit command that controls spinup and spindown that can be controlled under any OS that has a driver that supports it, including Linux. SATA also has NCQ and a few other features going for it, and the price difference isn't too bad if you buy drives on sale. But to each his own.

The flexibility point has to do with being able to run arrays that cross over hardware controller boundaries, and also being able to map in spares on alternate controllers. For example, if you started out with a 4 port RAID card, and then wanted to add another disk to the RAID 5 configuration on an alternate controller, then software RAID will let you do it, at least under Linux it will. If you had 2 RAID 5 arrays in a RAID 50 configuration, you run into issues if that covers more than 8 drives which the is max I have seen hardware controllers support.

I think broadcom has been working on cross controller arrays, but it's more of a hardware assisted RAID than 3ware's hardware RAID, so it may be kind of a hybrid solution.

If you know what you are going to build up front, then you can pay extra for controller ports you want etc... (up to 8), and then add according to your plan. But if you decide to change directions at somepoint, Linux software RAID has more flexibility (like adding a 2nd RAID 5 array and doing a RAID 50 stripe between the two arrays). I don't think you can find these features in the small enterprise class array controllers we are discussing here.

Thanks,
Mike

[stanger89]

3ware offers cards with up to 12 ports per card. Plus multiple controllers in one PC, although I don't think they support arrays across controllers. One thing to consider is the value of spanning/raiding controllers together, we're talking at least 2TB/controller these days. Another thing to consider...\

edit.

I was about to discuss the 2TB limitation of many file systems, but you learn something new every day:

In theory, the maximum NTFS volume size is 2^64 clusters minus 1 cluster. However, the maximum NTFS volume size as implemented in Windows XP Professional is 2^32 clusters minus 1 cluster. For example, using 64-KB clusters, the maximum NTFS volume size is 256 terabytes minus 64 KB. Using the default cluster size of 4 KB, the maximum NTFS volume size is 16 terabytes minus 4 KB.

There's an interesting table on that page too.
http://www.microsoft.com/resources/d...c_fil_tdrn.asp

Found it interesting, I've seen posted (not necessarilly here) that XP Pro was limited to 2TB (2^23 bytes) volume sizes, looks like it's actuall 2^32 * cluster size.

[DougTea]

Guys,

I just implemented another server running RAID 5 and I am stoked (stanger, thanks for the response over at the avsforums)!

I decided on a Adaptec SATA card as I've been using their SCSI adapters for years and their model currently supports OCE. My drives are 300gb and with the 8 port card I've hit 2.1 TB.
I wanted a dedicated media server instead of using my sage tv server as "the media server". The sage server has a 600 gb array so there's enough space to record and store shows that have not been edited. My reasoning of two servers was because I didn't want to record tv to a network share. With 6 sage clients I felt my network would halt if a couple of shows were recording simultaneously. My son likes to play ripped ISOs while my wife and I stream different shows from the sage tv server.
Once I 'VideoRedo' the recordings I then move the edited recordings to the new server. With this said ... music, photos, ripped DVDs and edited tv recordings all sit on the new server while 'recorded tv' (not yet edited) remains on the sage server.
I placed this new machine in a spare closet and added one of those small floor air conditioners. Works perfectly.

Doug

[mdmint]

Originally Posted by DougTea

Guys,

I just implemented another server running RAID 5 and I am stoked (stanger, thanks for the response over at the avsforums)!

I decided on a Adaptec SATA card as I've been using their SCSI adapters for years and their model currently supports OCE. My drives are 300gb and with the 8 port card I've hit 2.1 TB.
I wanted a dedicated media server instead of using my sage tv server as "the media server". The sage server has a 600 gb array so there's enough space to record and store shows that have not been edited. My reasoning of two servers was because I didn't want to record tv to a network share. With 6 sage clients I felt my network would halt if a couple of shows were recording simultaneously. My son likes to play ripped ISOs while my wife and I stream different shows from the sage tv server.
Once I 'VideoRedo' the recordings I then move the edited recordings to the new server. With this said ... music, photos, ripped DVDs and edited tv recordings all sit on the new server while 'recorded tv' (not yet edited) remains on the sage server.
I placed this new machine in a spare closet and added one of those small floor air conditioners. Works perfectly.

Doug

You must be referring to the Adaptec 2810SA, sweet! Only thing sweeter would have been the 21610SA with it's up to 16 drives! BTW, did you get the optional (IRRC) battery backup module for protected write back caching? I've had the ATA100 2400A for a number of years, rock solid controller, though as of a couple weeks ago it's currently sitting in box.

I some what compromised to save $$$ building my Sage Server and went 3ware 9500S-8 figuring since maxing it out HD wise initial config wasn't concerned with it's lack of OCE support.

[DougTea]

mdmmint,

Yes, the 2810sa! Trust me mdmmint, I wanted the 21610SA and would have purchased it providing cases holding 16 drives were somewhat affordable.

The card was purchased retail from newegg and the battery backup wasn't an option. I do have the server hanging off of a 60 minute UPS connected via USB ...so if needed, the server will gracefully shutdown.

I debated between the Adaptec and 3ware cards (are there really any others worth considering?) But decided past experiences with Adaptec made me more comfortable.

I searched extensively for external cases to store the hdds in but I had no luck. The only option I could find out there was from Adaptec which was called the "SanBLOC" ....of course it supports SATA drives but conencts to the host via SCSI. I was hoping to build a netapp type of solution. ...Oh well maybe next time!


mdmmint, at least you have a card for your next array.

Merry Christmas,
Doug

[mdmint]

Originally Posted by DougTea

mdmmint,
The card was purchased retail from newegg and the battery backup wasn't an option. I do have the server hanging off of a 60 minute UPS connected via USB ...so if needed, the server will gracefully shutdown.


mdmmint, at least you have a card for your next array.
Merry Christmas,
Doug

Me too UPS wise, SageServer on APC1500 with addon battery pack for 90+min runtime full load.

Adaptec 2400A wise it'll be my 3rd RAID5 home system when I put it back into production. The 3ware 9500S-8 for SageServer with 8x250 Sata RAID5 w/online spare, Promise FastTak S150 SX4 in my main workstation currently 2x250 Sata mirrored with plans to add two more and live migrate from RAID1 to RAID5 (supports both online RAID conversion and expansion (eBay bidding on them now, trying to get them under $0.50/MB), BTW Promise controllers have some nice features too ). Then I'll look at picking up 4 humungo ATA100 HDs for the 2400A even more storage if/when needed. When is enough enough? Never!

[infiniti_guy]

What do you guys think about the RAID 5 on the ASUS K8NE MoBo? It comes with 4 Channel SATA RAID 5. With 300-400GB Drives.. This could provide decent storage.

[infiniti_guy]

Now that Sage is going Linux, do you guys think that the SW RAID with a Linux server is the real solution?

[stanger89]

I don't think the nForce natively supports RAID-5, which would indicate that it's some sort of driver hack on ASUS part, in which case I don't like it.

[infiniti_guy]

The ASUS board has an extra SATA Controller

"Silicon Image Sil 3114 SATA controller
4 x Serial ATA
RAID 0, RAID 1, RAID 10, RAID 5, JBOD"

In addition to the nForce3 chipset features... I don't know if that would work well, I was wonderign what you guys thought...

[mdmint]

Originally Posted by stanger89

I don't think the nForce natively supports RAID-5, which would indicate that it's some sort of driver hack on ASUS part, in which case I don't like it.

Whoa, new AMD 64 Nvidia ASUS mobo in town! Just checked and it does support a 4 drive SATA RAID 0,1,5,10 AND 2 drive SATA RAID 0,1 at the same time, using two different chipsets. (plus two PATA connectors with RAID 0,1 support) Wouldn't be caching controllers but not bad at all.
http://www.asus.com/products/mb/sock...d/overview.htm

[mdmint]

Originally Posted by infiniti_guy

Now that Sage is going Linux, do you guys think that the SW RAID with a Linux server is the real solution?

I never did.

[infiniti_guy]

I looked at the Drivers on ASUS for that Mobo and I'm not sure if the RAID can be used with Linux (It looks like they just have Win Drivers). I am concerned about having an easy migration to Linux when Sage switches their platform.

I just got back from CES, so I spoke w/Dan about their new "plans".

[mdmint]

Originally Posted by infiniti_guy

What do you guys think about the RAID 5 on the ASUS K8NE MoBo? It comes with 4 Channel SATA RAID 5. With 300-400GB Drives.. This could provide decent storage.

Since you mentioned it been looking at that mobo thinking about my next workstation upgrade. (Don't really NEED the RAID5 caching controller that's in it - Promise FastTrak S150 SX4) But for a dedicated Sage Server I wouldn't necessarily go that way. Believe better off with better more expandable caching RAID5 controller and since you in no way need AMD 64 CPU horsepower for Sage Server use AMD XP (any speed will work), spend the money saved on fastest most expandable RAID5 HD subsystem. Escalade & Adaptec have very scalable SATA solutions, Promise controllers also good IMO but not as scalable internally. My SageServer even when 5xRecording @ DVD Std and feeding play back keeps up no problem. XP 2100 CPU hardly working, 7x250 SATA RAID5 Escalade 9500S-8 w/256MB cache keep up no problem.

[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.