Drobo

How to Save Windows Home Server: Vail + Drobo

http://community.winsupersite.com/blogs/paul/archive/2010/12/01/120927.aspx

I cant figure out if he means simply attaching a drobo (maybe even internally) to a WHS box, or…

does he actually mean recompiling Drobo’s secret sauce to run on x86 windows and actually just have it as a single box.

i guess the drobo’s firmware and processor could essentially just be a PCI-E add-in card to the box anyway - acting as the drive controller, so it probably wouldnt make any difference to the end user.

I think Bhiga is a WHS guy - he’ll no doubt have strong opinions on the drive extender fiasco

Yup, I do have strong opinions on the DE fiasco…

Keeping in mind that I came from Server 2K3 Enterprise with RAID that I built…
I use WHS for three reasons:

  1. Storage pooling. This is Drive Extender. Multiple drives act together as one logical unit.
  2. Automated backup.
  3. Extensibility (I’m a Windows guy, so I have lots of other services/apps that I can run on the platform)

Those also happen to be in order of importance to me.

The implication that Drobo could “replace” WHS is a bit far-off in my mind.
Drobo does storage expansion - but currently it does not do storage pooling. Meaning you can expand a single Drobo’s capacity to whatever the current limit is based on drive size.

WHS Drive Extender’s storage pooling is a bit different. It allows for multiple drives to be pooled together. In my case, since I use Drobo as the drives in my storage pool, I have two Drobo v2 units with 5.5 TB usable each (4x2TB drives), so I have “one big pool” of 11 TB. I could add the other Drobo v2 unit with 5.5 TB to my storage pool, bringing my storage pool to 16.5 TB, but I’m not that full yet, so that Drobo unit I use as a backup.

Yes, I could condense my storage to a single DroboPro with 8 drives and have 14.55 TB in my storage pool, but what happens when I need more than 14.55 TB of storage?

That’s where DE comes in, I could add another Drobo, DroboPro, or just a plain old drive to it. Expansion without having to wait for 3 TB drives or larger to become affordable. Granted, larger drives in fewer units makes for more power efficiency…

DE also has a function called Duplication which essentially operates as RAID 1 mirroring on a file level (for all files within a share).

However, proper functioning of that feature requires that WHS is ‘aware’ of each physical drive.

Since WHS doesn’t support GPT volumes for DE (even though the core OS does support GPT), each of my Drobos end up looking like three 2 TB drives, so WHS v1 can’t maintain a “one physical drive to one physical device” relationship for anything larger than 2 TB.

That’s why I don’t use Duplication, aside from the fact that it’s not storage-efficient.

So I was really looking forward to WHS v2 since it was going to support GPT for the storage pool, but now that DE has been pulled, there’s no reason for me to upgrade.

I’m more than a bit disappointed.

from what i was reading DE v2 was going to do it at the block level, and simply proved an interesting combination of too difficult and not backward compatible.

as anand so concisely puts it:

http://images.anandtech.com/doci/3677/DEv2b.png

In theory it would’ve worked better, but I think they got too “nitty gritty.”

I’d be happy if they just enabled GPT support for DEv1. That’s all I really want… 64-bit core would be nice, but I’m fine right now.

FYI, I moved to WHS 2011 (aka Vail).

I’m using Drive Bender with my two Drobo Gen2’s, both set as 16TB GPT volumes.

Things are working fine so far, and Drive Bender actually does balance the storage usage, unlike WHSv1’s Drive Extender which had a weird “wait until it’s this full, then start moving data off like a madman” balancing strategy.

So far, so good. knocks on wood

As an aside, Linux has a thing called LVM (Logical Volume Management, http://en.wikipedia.org/wiki/Logical_volume_management ) that can do storage pooling, etc. It lets you add drives to logical volumes, and even move data off one drive to another drive to allow you to make changes, etc. You can even combine it with RAID to do all kinds of interesting setups.

I used to use this on the old PC I used as a media server before I got a Drobo - 8 old hard drives of all sizes and interfaces all pooled into one big volume. Very cool. The coolest thing was moving my home accounts to another drive WHILE I WAS USING IT so that I could take out a drive I wanted to retire. Bit geeky, lots of command line, but something that someone could write a nice GUI around.

Good to know!

Sound very similar to what DB does (mix multiple physical volumes as a logical unit, set up virtual volumes, etc). Pairs nicely with my Drobos. If I lose a single drive, Drobo takes care of it. If I lose an entire Drobo, at least the stuff DB had duplicated survives in latest-state (yes, it’s more wasted space compared to DDR/RAID6 but don’t have the funds to jump to that yet). If I lose the entire server … there’s my backup.

So far I really like Drive Bender - it sits atop NTFS, so in an emergency I could just pull the volumes and read them on another machine, without having to deal with the tombstone craziness from WHSv1’s DE.

LVM is precisely what Netgear uses in their ReadyNAS appliances. They set up multiple logical volumes across the drives, and use different RAID levels depending on the requirements of the volume (eg. RAID 1 for the OS, RAID 5 or 6 for the data volumes, etc).
It’s simple, elegant, works very well, and the volume set can be read in regular Linux systems if necessary.

As you say, the real key is the management tool. ReadyNAS does that well.

For my next RAID set, I’m going to play with RAIDZ. If it works, it will be brilliant. “If.”

LVM is also how synology hybrid raid works

Mmm… If my wife gets her way and we get a rack, there is a high likelihood something in it will be using LVM…
But strangely I resist… not that I’m pro-MS or anti-Linux… I’m just anti-bringing-huge-rack-up-three-flights-of-stairs! I’ve been doing well getting RID of big/heavy stuff! :slight_smile: