SageTV support for Asus Wifi/TV Tuner ?

[SteinyD]

Ah, 'backup'. Yes, there will be an external hard drive connected to the home router at some point (soon) to serve as backup. But I do want redundancy in the local machine as well. So which Raid would you recommend?

And yes, I'll do a standalone drive for OS,etc. This is actually what my current configuration is. I'll look for a speedier drive (raptor or such) as that drive and the 8mb or 16mb cache drives for the raid storage.

Thanks!
David

Originally Posted by stanger89

Firstly, redundancy is a suppliment to backup, not a replacement. Now that that's out of the way

By video editing, I assume you mean hacking commercials, and otherwise messing with recorded video of some sort? Remember, recorded video, even HDTV is under 3MB/sec data rate, so anything beyond a single drive performance isn't likely something you'll need.

I think if you go with a single drive for the OS/apps, and probably scratch data, and then the array for the more static stuff, you'll be good to go.



If you want speed for apps and such, what you need to do is reduce latency, that means 10000rpm drives. I'd go with either a Raptor. If you're going to need more than 74GB for transatory data (OS/Apps, temporary editing files, etc) then one of the large 7200rpm drives with 8MB cache would work well.

h

[stanger89]

Originally Posted by SteinyD

Ah, 'backup'. Yes, there will be an external hard drive connected to the home router at some point (soon) to serve as backup. But I do want redundancy in the local machine as well. So which Raid would you recommend?

If you're talking 4 drives total (or especially if you plan on more), then I really like RAID-5.

[SteinyD]

So let me throw a wrench into this conversation. I've been looking at drives labeled as 'SATA II', assuming they were the next generation of SATA technology. I did notice however, that as I looked at the specs of the drives, they didn't all offer increased performance or even the same spec. I came across this article today which leads me to believe what we are currently seeing as 'SATA II' is a farse!

http://www.anandtech.com/storage/showdoc.aspx?i=2450

[SteinyD]

Stanger89 -

I just came across this thread which fits into our discussion perfectly. Though most agree with backups versus redundancy, I too agree that Raid 5 technology seems to be a more cost effective way to do large scale backups, using a separate drive or DVDs to backup critical data.

http://www.anandtech.com/news/shownews.aspx?i=23625

So that I make sure I understand. In a Raid-5 configuration, if I have a drive failure - I can 'hot swap' that drive without loss of data? And it can be any ONE of the drives in the array? Second question - Raid-5 is 3 or more drives? Do the need to be added in certain multiples? Do they always need to match (same spec)?

Thanks,
David

[stanger89]

Originally Posted by SteinyD

I came across this article today which leads me to believe what we are currently seeing as 'SATA II' is a farse!

No more than ATA133, heck even ATA66 was. You're right drive technology, not the interconnect technology is the limiting factor. WD Raptors (the fastest SATA drives available) can only do just over 70MB/sec sustained. Even the fastest 15k SCSI drives can only do just over 90MB/sec.

However (and I haven't reasearched this) SATA II does offer one very interesting thing, port mulipliers, they turn one SATA II port into 5, in that situation the extra port bandwidth would almost certainly be welcome.

[SteinyD]

Stranger - see my message at 3:38 above. Could you clarify the Raid-5 quesiton. I'm about to pull the trigger and thinking I'm buying 4 250 gb drives. 3 will be on Raid-5 and one will be a standalone, boot drive with the OS and key apps. But, want to make sure I understand the configuration and ability of Raid-5 (per my note above).

Thanks again!
David

[stanger89]

Sorry didn't see that one

Originally Posted by SteinyD

Stanger89 -

I just came across this thread which fits into our discussion perfectly. Though most agree with backups versus redundancy, I too agree that Raid 5 technology seems to be a more cost effective way to do large scale backups, using a separate drive or DVDs to backup critical data.

http://www.anandtech.com/news/shownews.aspx?i=23625

Just want to state this as I went on at length about it in a thread at AVS recently. Don't confuse RAID with backup, they are completely different animals. RAID is redundancy, meaning protection against fialure of the specific component, ie protection against drive failure. It doesn't protect against software/virus/user failure. You probably understand this, but I just want to make sure it's clear.

So that I make sure I understand. In a Raid-5 configuration, if I have a drive failure - I can 'hot swap' that drive without loss of data?

RAID-5 can survive the failure of any single drive, now the ability to Hot Swap (ie replace the failed drive without powering down the system) is dependent on your RAID controller. If your controller doesn't support hot-swap, then it's just a matter of powering down your machine to replace the failed drive.

And FWIW, the better controllers out there support Hot Spare, where there's one disk connected to the card that sit's idle, and in the event of a failure the RAID controller automatically removes the failed drive, inserts the Hot Spare, and starts rebuilding the array. Why is that good, because when while the drive is failed, and while the array is rebuilding, it is no longer fault tolerant, a second drive failure before finishing a rebuild, will result in loosing all data.

And it can be any ONE of the drives in the array?

Yes, any one of the drives.

Second question - Raid-5 is 3 or more drives?

Yes, RAID-5 requires at least 3 drive, (2 drives would be RAID-1)

Do the need to be added in certain multiples?

Now you need an OCE capable controller to add drive to an existing array, but no RAID-5 supports an arbirary number of drives.

Do they always need to match (same spec)?

They don't have to, but you'll get the best performance if they do. Right now I'm running 8 250 GB WDs, but they are not all the exact same model. In the past I've run RAID-5 with different models. Just remember the size of the array will be limited by the size of the smallest drive.

[SteinyD]

Thanks again for the time taken for the response. Yes, completely understand the difference between 'backup' and 'redundancy'. Backup will be taken care of in some other manner - likely data to DVDs, etc.

You said that that the size of the array is limited by the size of the smalled drive. If I have a Raid-5 array of 4x250gb drives, how much total net storage do I have?

I want to make sure that I am understanding what you are saying about raid-5 for hardware failure. If a hard drive in an array fails and I replace it, is there data loss from that failed drive?

Originally Posted by stanger89

Sorry didn't see that one



Just want to state this as I went on at length about it in a thread at AVS recently. Don't confuse RAID with backup, they are completely different animals. RAID is redundancy, meaning protection against fialure of the specific component, ie protection against drive failure. It doesn't protect against software/virus/user failure. You probably understand this, but I just want to make sure it's clear.



RAID-5 can survive the failure of any single drive, now the ability to Hot Swap (ie replace the failed drive without powering down the system) is dependent on your RAID controller. If your controller doesn't support hot-swap, then it's just a matter of powering down your machine to replace the failed drive.

And FWIW, the better controllers out there support Hot Spare, where there's one disk connected to the card that sit's idle, and in the event of a failure the RAID controller automatically removes the failed drive, inserts the Hot Spare, and starts rebuilding the array. Why is that good, because when while the drive is failed, and while the array is rebuilding, it is no longer fault tolerant, a second drive failure before finishing a rebuild, will result in loosing all data.



Yes, any one of the drives.



Yes, RAID-5 requires at least 3 drive, (2 drives would be RAID-1)



Now you need an OCE capable controller to add drive to an existing array, but no RAID-5 supports an arbirary number of drives.



They don't have to, but you'll get the best performance if they do. Right now I'm running 8 250 GB WDs, but they are not all the exact same model. In the past I've run RAID-5 with different models. Just remember the size of the array will be limited by the size of the smallest drive.

[stanger89]

Originally Posted by SteinyD

Thanks again for the time taken for the response. Yes, completely understand the difference between 'backup' and 'redundancy'. Backup will be taken care of in some other manner - likely data to DVDs, etc.

You said that that the size of the array is limited by the size of the smalled drive. If I have a Raid-5 array of 4x250gb drives, how much total net storage do I have?

You'll have (n-1)* capacity of smallest drive, ie (4-1)*250 or 750GB of useable space.

What I meant was you could use 1 200GB drive and 3 250GB drives, but you'd have (4-1)*200, or 600GB then.

I want to make sure that I am understanding what you are saying about raid-5 for hardware failure. If a hard drive in an array fails and I replace it, is there data loss from that failed drive?

If a harddrive fails, the array becomes "degraded" meaning the redundancy is gone, but you'll still be able to use the array, you can read/write, etc, but it will be slower because it has to recalculate (XOR) for what was on the now failed drive. No technically there is lost data, but that data can be rebuilt from the info on the other drives. So net, you don't actually loose anything.

Basically with RAID-1 you keep a 1:1 copy of the info on the mirrored drive. With RAID-5 it's not 1:1, it's parity info, ie if drives 1,2,3 have 1,0,1, drive for will have 0. With RAID-1 you know what's on drive 1 because it's on drive 2, with RAID-5 you know what's on any given drive because it's just the XOR of what's on the remaining drives.

[SteinyD]

I got it now! :-) Thanks again for the detailed conversation on this topic.

Now back to the original thread subject. If I'm going to continue to use SageTV for my timeshift recording software, is the Hauppauge cards (350 or 500) my best option for a tuner card? I use the recorded content in several ways. Though I occasionally watch the content from my pc, I more often encode the content for viewing on a portable device such as the Archos AV-420 or more often then not, I burn them to DVD for watching on a tv (or pc) at a later time.

Regards,
David

Originally Posted by stanger89

You'll have (n-1)* capacity of smallest drive, ie (4-1)*250 or 750GB of useable space.

What I meant was you could use 1 200GB drive and 3 250GB drives, but you'd have (4-1)*200, or 600GB then.



If a harddrive fails, the array becomes "degraded" meaning the redundancy is gone, but you'll still be able to use the array, you can read/write, etc, but it will be slower because it has to recalculate (XOR) for what was on the now failed drive. No technically there is lost data, but that data can be rebuilt from the info on the other drives. So net, you don't actually loose anything.

Basically with RAID-1 you keep a 1:1 copy of the info on the mirrored drive. With RAID-5 it's not 1:1, it's parity info, ie if drives 1,2,3 have 1,0,1, drive for will have 0. With RAID-1 you know what's on drive 1 because it's on drive 2, with RAID-5 you know what's on any given drive because it's just the XOR of what's on the remaining drives.

[SteinyD]

You know what Stanger89, I lied. I need to fall back on the raid conversation one more time. Unless you told me this already, what is wrong with Raid 1 on a home PC? I realize from net storage capacity, I'm at 50% of the pair. But if I have a pair of 500 gb drives, isn't this the easiest way to stay redundant? If a drive dies, I still have the other drive. If all of that is true, can I simply replace the failed drive with a new one and I'm back up and running with redundant drives?

[stanger89]

Yes, with 2 drives, RAID-1 is your only option, beyond that RAID-5 can be really nice due to the storage efficiency.

[SteinyD]

Sorry, i just can't help myself. I was just reading a thread of messages on anandtech of a discussion re: pros/cons of raid technology, etc. Someone suggested that they have a setup of - 2x Raptor drives in Raid-0 for the O/S, 2x400gb for Raid-1 and an external drive / tape backup. This almost sounds more sensible to me than setting up a Raid-5 array. No?

What if I want to add more storage (the 400gb Raid-1 isn't enough). Is raid-1 only a pair of drives? Am I stuck at that point? Does Raid-5 give me the ability to add additional drives to the array without a complete rebuild?

[stanger89]

Originally Posted by SteinyD

Sorry, i just can't help myself. I was just reading a thread of messages on anandtech of a discussion re: pros/cons of raid technology, etc. Someone suggested that they have a setup of - 2x Raptor drives in Raid-0 for the O/S, 2x400gb for Raid-1 and an external drive / tape backup. This almost sounds more sensible to me than setting up a Raid-5 array. No?

Depends, IMO the pair of Raptors in RAID-0 is a waste of money, as I liked above, RAID-0 does not offer a performance advantage in most cases. As for the 2x400GB, if you've only got 2, your only choice is RAID-1. But total you've got 150GB of non-redunant storage and 400GB of redundant storage, 550 total.

What I think would be better, is 1x Raptor for OS/etc, and 3x 300GB drives in RAID-5. That give 74GB non-redundant storage + 600GB redundant storage for a total of 674GB. The cost would be similar depending on RAID controller.

If you trade the 300s for 400 (more costly) you'd have 874 GB.

There's lots of ways to go, I think you've got a handle on the basics, plusses/minuses.

What if I want to add more storage (the 400gb Raid-1 isn't enough). Is raid-1 only a pair of drives?

RAID-1 is mirroring, ie one thing mirroring another.

Am I stuck at that point?

Not necessarilly, it will depend on your controller, but you can combine arrays, eg RAID-01 or RAID-10. What that is, a mirror (RAID-1) of 2 striped arrays (RAID-0), or a stripe of mirrored arrays (RAID-10).

What you could do is take 4 400GB drive, make two RAID-0 arrays, and then mirror them, giving you a net of 800GB of space. I'll let storagereview explain the differences between 10 and 01:
http://www.storagereview.com/guide20...ls/multXY.html

Does Raid-5 give me the ability to add additional drives to the array without a complete rebuild?

Online Capacity Expansion (OCE) gives you the ability to add drives to the array, without loosing the data in the array. I'm trying to be carefull here, because you will still have to "build" or "rebuild" the array to add the new drive, but data is not lost. Vs, non OCE where you must destroy the array and create new to add a drive. It's not inherent to RAID-5, but an addition feature implimented by the RAID controller.

Oh and one more thing, you will also (separately) need to resize the partition (or add a new one) on the expanded array, OCE doesn't resize/expand partitions. However there are apps out there that can do that "on the fly", such as Acronis Disk Director.

[SteinyD]

Ok, I promise - not another question about drive arrays! :-) You've provided more information and education then I thought I'd get! Its much appreciated.

Mixed in my volley of messages above, I thought I might drive us back to the topic of this website - PVR and tuner cards! :-)

If I'm going to continue to use SageTV for my timeshift recording software, is the Hauppauge cards (350 or 500) my best option for a tuner card? I use the recorded content in several ways. Though I occasionally watch the content from my pc, I more often encode the content for viewing on a portable device such as the Archos AV-420 or more often then not, I burn them to DVD for watching on a tv (or pc) at a later time.

Options? Hauppauge best way to go for compatibility with Sage and features of encoding?

Again, thanks .. seems you and I need to do something more on Saturday then hang out at this forum! ;-)

David

[Kanati]

we're putting together a raid50 box at work right now... literally so much redundancy that we could lose 10 drives at the same time without worrying about it.

[gplasky]

RAID 50 is just multiple RAID 5 sets with data striping. You can lose multiple drives but you're still limited to losing one drive per each RAID 5 set. You're still screwed if you lost 2 of those drives on a single RAID 5 set. An EMC Sysmetrix DMX800 only supports up to 8 hypervolumes or RAID sets so on those you can only lose 8. I'm curious as to what box you're setting up.


Gerry

[SteinyD]

Gerry:

Please read through this thread for the specs. This is a home based pc and not a commercial application. I was looking for an appropriate level of redundancy, protecting both system (hardware) and data. I completely recognize the virtues of 'backup' versus redundancy but still want to provide a secondary layer of protectioin for the hardware and the software that resides on it.

Again, reading through the thread I've come to the conlusion (with great help from others in this thread) that a primary, standalone drive for OS and primary application and a Raid-5 array of 3-4 drives for data will provide an adequate solution. For backup, I will be installing something like a Lacie drive connected to the home router. These drives will be connected to an Asus P5WD2 Premium motherboard that has support for Raid via Serial ATA controllers.

Regards,
David

Originally Posted by gplasky

I'm curious as to what box you're setting up.


Gerry

[gplasky]

I should have made it more clear my reply was for Kanati's post just above. Hence the comment about RAID 50.

I have mine set up for the OS/Boot drive on a 100GB drive and I have that imaged with the image stored elsewhere. My 3 x250GB drives are in a RAID 0 + 1 on the internal SATA to take advantage of the speed benefits of striping across all the drives. For playing back video, audio and streaming the speed benefits seemed to make more sense to me. So far I've had no issues and the PC has been available 24/7. I didn't see the need to go to RAID 5 on a HTPC.

Gerry

[SteinyD]

Sounds appropriate for a HTPC. My solution is not a HTPC. This is a workstation that I use at home for editing and encoding / burning video, browsing, PVR capabilities (use of SageTV and tuner card on this pc) and storage of video / audio library.

Regards,
David

Originally Posted by gplasky

I should have made it more clear my reply was for Kanati's post just above. Hence the comment about RAID 50.

I have mine set up for the OS/Boot drive on a 100GB drive and I have that imaged with the image stored elsewhere. My 3 x250GB drives are in a RAID 0 + 1 on the internal SATA to take advantage of the speed benefits of striping across all the drives. For playing back video, audio and streaming the speed benefits seemed to make more sense to me. So far I've had no issues and the PC has been available 24/7. I didn't see the need to go to RAID 5 on a HTPC.

Gerry