HP ProLiant MicroServer

NAG - Wesley said:
Why not use RAID 5? You can build the array off 3 drives and add as time passes. The space available would be 1-1/n where n is the number of drives available. So three 2TB drives results in: 6-1 = 5TB of useable space. The rest is for parity. All you'd need is identical space drives with the same rotational speed and a good UPS system that switches onto battery backup almost immediately. And all you'd have to do is add in one drive every two to three weeks to make up for the parity distribution and to allow the array to scale accordingly. Once you reach something monstrous like 24TB then it'd probably take two months to scale up the array.

The only caveat is that you're still only allowed one drive failure, so I'd only build a RAID 5 array to six drives for less complexity. RAID 6 can tolerate two failures, so that'd allow me to go up to ten 2TB drives for a total of 18TB. RAID six leaves you with more flexibility, but requires four drives from the start. I'd also only use these arrays with dedicated PCI-E 4x cards, as the rebuild is a taxing and time-consuming process. Having dedicated hardware do it in idle time is better in the long run. Having said that, a motherboard without RAID add-in cards that is just used as a server would do the job just as well, with a little performance deficit. You'd be limited to RAID 5, but that's enough for most home media servers anyway.



I like that idea, but again you'd need proper hardware to do it and the caveat is that it stores information across one, two or a group of drives as opposed to an entire RAID array. The benefits are scalability and rebuild time, but the write performance differs according to which drive the data is stored on and how fast that one is. unRAID is a great idea in a dedicated server that's going to be in use for years, not so much for desktop use or for HTPC.

I'd say for desktop use, mirrored RAID is a good starting point with two 500GB drives as the mirror and other drives in a higher level of RAID connected to a dedicated card. I'll be going for a mirrored setup for my next machine if I find that SSDs wont cut it for me. Perhaps Trim support gets implemented in RAID in the future, but for now its not as viable.
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I already have one 4 drive RAID-5 setup, which I could add more drives too but I am planning to move over to zfs. As soon as I have set up my new zfs array then I will move the data over from the old RAID-5 setup to the zfs setup and then add those drives to the zfs setup. I feel very uneasy running software RAID, as I have already lost almost 2TB of data due to faulty sata connectors on a motherboard and it seems so temperamental. The way zfs is designed makes it a lot more structured and secure, only problem is I'll be needing another box. 12TB here I come! (as soon as hdd prices even out :()
 
NAG - Wesley said:
You have to do RAID off the bat, else it won't work. Keep the 250GB, add in the 2TB mirror array for your media. There's little chance the 250GB will fail anyway thanks to the single platter and 7200rpm rotational speed.
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I set up initially on the 250.
Then when I got a pair of 1.5s, I removed the 250, installed the 1.5s, freshly installed openelec on the mirrored pair I created, then popped the 250 into the 3rd drive bay and copied over the xbmc config and storage directories. Shutdown, remove drive, reboot... all old settings and content was there :)
 
NAG - Wesley said:
I like that idea, but again you'd need proper hardware to do it and the caveat is that it stores information across one, two or a group of drives as opposed to an entire RAID array. The benefits are scalability and rebuild time, but the write performance differs according to which drive the data is stored on and how fast that one is. unRAID is a great idea in a dedicated server that's going to be in use for years, not so much for desktop use or for HTPC.

I'd say for desktop use, mirrored RAID is a good starting point with two 500GB drives as the mirror and other drives in a higher level of RAID connected to a dedicated card. I'll be going for a mirrored setup for my next machine if I find that SSDs wont cut it for me. Perhaps Trim support gets implemented in RAID in the future, but for now its not as viable.
Click to expand...

On the contrary. Mass storage i.e. HTPC is where unRAID shines and you don't need serious HW. From the docs: http://lime-technology.com/technology
Lime Technology believes that there is a market for a new wrinkle on the old RAID technology. Our approach uses a storage organization we call unRAID™. unRAID™ is similar to RAID-4 in that for every n hard drives, there are n-1 data drives, and a single fixed parity drive. This provides similar drive failure protection as other RAID organizations:

Tolerates a single failed hard drive. Array parity permits reconstruction of a single failed data disk.
Tolerates single drive read errors . Read errors from a single disk are corrected "on-the-fly".

Unlike other RAID organizations, however, files are not striped across the data drives. Instead, each data drive is formatted normally with its own file system. The unRAID™ organization offers several key advantages over other RAID systems:

Increased flexibility: not all hard drives need to be the same size or speed. The only requirement is that the parity drive must be as large as or larger than any of the data drives.
Easier expansion: new data drives may be added to the array without disturbing the data on the other drives. Since data is not striped, no lengthy stripe reorganization needs to take place before the new storage is available.
Better fault tolerance: in the unlikely event of catastrophic hardware or software failure, data corruption would be much more isolated than that which could occur with other RAID organizations. It is almost impossible to lose all your data, since each individual data drive has its own file system.
Better power management: not all hard drives are required to be spinning in order to access data normally; hard drives not in use may be spun down.
Potentially better multiple-stream read performance. If multiple files are read from different disks, overall read performance can be higher than with other RAID organizations.

All Lime Technology server products are based on unRAID™ technology. We believe our products offer superior features and value in the digital media storage market.
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dualmeister said:
LOL. You do not use cheap desktop drives in a setup like that. That's what RAID class drives were designed for. One word ... vibration.
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Definition of raid - Redundant Array of INEXPENSIVE disks....
So yes, you use cheap disks.
 
NAG - Wesley said:
Why not use RAID 5? You can build the array off 3 drives and add as time passes. The space available would be 1-1/n where n is the number of drives available. So three 2TB drives results in: 6-1 = 5TB of useable space.
Click to expand...
6-2 = 4TB... Just saying...
 
fxit_man said:
Actually it was changed to "INDEPENDENT" a while ago now.
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Doesn't change the fact that the point of it is to create reliability and performance for minimal cost. So the point remains - you don't need top-of-the-range disks in a decent raid setup.
 
Enterprise drives have built in features which make them suitable for large scale environments (which is why they are more expensive).

Once you start having issues using desktop drives in a big RAID setup the manufactures are all going to tell you the same.

They are not suitable.
 
dualmeister said:
Enterprise drives have built in features which make them suitable for large scale environments (which is why they are more expensive).

Once you start having issues using desktop drives in a big RAID setup the manufactures are all going to tell you the same.

They are not suitable.
Click to expand...

Wait, so an "enterprise class raid drive" has a shorter error recovery timeout? How much extra does that little firmware setting cost?
Sounds like artificially creating a demand to me ;)
 
Sinbad said:
I set up initially on the 250.
Then when I got a pair of 1.5s, I removed the 250, installed the 1.5s, freshly installed openelec on the mirrored pair I created, then popped the 250 into the 3rd drive bay and copied over the xbmc config and storage directories. Shutdown, remove drive, reboot... all old settings and content was there :)
Click to expand...

Or that, you could just do that. Seriously, why do headaches have the power to make people stupid?

morkhans said:
On the contrary. Mass storage i.e. HTPC is where unRAID shines and you don't need serious HW. From the docs: http://lime-technology.com/technology
Click to expand...

That's true, but you'd still need a large parity drive for an unRAID array that's bigger than the average size of all the drives in the array. That's still a dedicated parity setup and once that or any other single drive fails, performance in the array drops as well. I also don't see mention of write speeds, therefore I assume its the same as writing to a single drive thats not in an array.

Also, when most people do RAID5, they bite the bullet and do it with multiple drives of the same size anyway. I'll be going for RAID6 for my media server when I get the money one day and a mirrored array for my desktop.

Sinbad said:
6-2 = 4TB... Just saying...
Click to expand...

Yup, that's the right number this time.
 
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