I have a client with a handful of USB drives connected to a CentOS box. I am charged with binding the USB drives together into a single LVM for a cheap storage data pool (10 x 1 TB usb drives = 10 TB cheap storage in a single mount point).
The next fun piece is how to incorporate that storage space into an existing Active Directory structure to apply AD acls for limited access.
I'd rather not use Samba, as that is its own infrastructure and maintains its own credentials database.
What are my best options?
Thanks.
Scott
Scott Ehrlich wrote:
I have a client with a handful of USB drives connected to a CentOS box. I am charged with binding the USB drives together into a single LVM for a cheap storage data pool (10 x 1 TB usb drives = 10 TB cheap storage in a single mount point).
The next fun piece is how to incorporate that storage space into an existing Active Directory structure to apply AD acls for limited access.
I'd rather not use Samba, as that is its own infrastructure and maintains its own credentials database.
What are my best options?
Why would you use USB disks? Even if you could put up with not-so-stellar speed, the tangle of cables & powerpacks would be messy and prone to accidental disconnect. On top of that, using only LVM to glue it all together would really exacerbate the disconnect problem. A single disk failure could bring the entire volume down with no recourse but to restore from backup.
That's another thing - is this data valuable? If so, you need to have an idea for backups.
Ditch the crazy USB scheme and get better hardware - raid/hotswap. And a 10 drive, 10TB raid5 is also going to be a headache. There's been several recent discussions here about such matters - large volume filesystems, SW raid vs HW raid, raid types, LVM, etc. Look through the archives.
Scott Ehrlich wrote:
I have a client with a handful of USB drives connected to a CentOS box. I am charged with binding the USB drives together into a single LVM for a cheap storage data pool (10 x 1 TB usb drives = 10 TB cheap storage in a single mount point).
The next fun piece is how to incorporate that storage space into an existing Active Directory structure to apply AD acls for limited access.
I'd rather not use Samba, as that is its own infrastructure and maintains its own credentials database.
The answer to your AD question is Samba. It integrates into AD perfectly well. Search the Centos archives. samba.org has extensive info on the subject.
Scott,
Samba is proven to work with AD, whats the other alternative? You can always tie Samba to the centralised credentials.
Scott Ehrlich wrote:
I'd rather not use Samba, as that is its own infrastructure and maintains its own credentials database.
Scott Ehrlich wrote:
What are my best options?
The mere thought of doing what your tasked with doing makes me want to drink a lot of hard alcohol.
As another poster noted get a more proper storage system. If it were me I would just hook the drives to one of the existing windows servers and use dynamic partitions to do the same thing, when a disk fails and they lose some/most/all of their data at least they won't be able to point the finger at linux
http://msdn.microsoft.com/en-us/library/aa363785(VS.85).aspx
There are plenty of low cost off the shelf NAS solutions, I don't have experience with any of them personally, but would absolutely positively never implement what your being tasked with. That client would not be worth keeping as they are obviously a @#$ idiot.
nate
What are my best options?
The mere thought of doing what your tasked with doing makes me want to drink a lot of hard alcohol.
I'll second that but say I want some alcohol anyway:) Keep in mind that most external usb enclosures don't provide adequate cooling for devices that get written to any more aggressively than some user and his pics collection.
The mere thought of doing what your tasked with doing makes me want to drink a lot of hard alcohol.
HA!
This thread really made my day.
I liken this to applying duct tape to the wings of a 747.
I would look out the window and say, "Neat!"
nate: that quote is going on my wall at work.
So long and thanks for all the fish.
On 12/15/09 2:48 PM, Scott Ehrlich wrote:
I have a client with a handful of USB drives connected to a CentOS box. I am charged with binding the USB drives together into a single LVM for a cheap storage data pool (10 x 1 TB usb drives = 10 TB cheap storage in a single mount point).
Err.. buy computer from supermicro and load it with 10 sata disks.
http://www.supermicro.com/products/chassis/2U/?chs=213
-- Eero
On 12/16/2009 12:10 AM, Eero Volotinen wrote:
On 12/15/09 2:48 PM, Scott Ehrlich wrote:
I have a client with a handful of USB drives connected to a CentOS box. I am charged with binding the USB drives together into a single LVM for a cheap storage data pool (10 x 1 TB usb drives = 10 TB cheap storage in a single mount point).
Err.. buy computer from supermicro and load it with 10 sata disks.
http://www.supermicro.com/products/chassis/2U/?chs=213
-- Eero _______________________________________________ CentOS mailing list CentOS@centos.org http://lists.centos.org/mailman/listinfo/centos
Still going to need 10TB of backups. And i can guarantee you the chances of having a URE during rebuild are almost certain with this setup so a backup is going to be crucial. Sounds like a nightmare even inside a supermicro or similar box.
On 12/16/2009 9:41 AM, William Warren wrote:
On 12/16/2009 12:10 AM, Eero Volotinen wrote: Still going to need 10TB of backups. And i can guarantee you the chances of having a URE during rebuild are almost certain with this setup so a backup is going to be crucial. Sounds like a nightmare even inside a supermicro or similar box.
Yah, RAID-6 at a minimum, I wouldn't depend on RAID-5, even with a hot-spare. So to get 10TB, you'd need 13 drives (10 data, 2 parity, 1 hot-spare).
And make sure you buy enterprise level SATA disks (the 1TB models are about $150 right now).
(You can fit 15 3.5" drives into a SuperMicro 4U 942i 760W case with the 5:3 SATA mobile racks. The 942i is also a very quiet case due to using 120mm fans inside.)
On Wed, Dec 16, 2009 at 09:57:38AM -0500, Thomas Harold wrote:
Yah, RAID-6 at a minimum, I wouldn't depend on RAID-5, even with a hot-spare. So to get 10TB, you'd need 13 drives (10 data, 2 parity, 1 hot-spare).
2TB drives are available for ~$300-$400 each. Eight 2TB disks would provide 10TB of RAID6 storage with a hot spare, which could all fit in a 2U enclosure or a smaller desktop case than a 13 or 16 bay case.
--keith
On Tue, 15 Dec 2009, Scott Ehrlich wrote:
I have a client with a handful of USB drives connected to a CentOS box. I am charged with binding the USB drives together into a single LVM for a cheap storage data pool (10 x 1 TB usb drives = 10 TB cheap storage in a single mount point).
I tried doing this for fun once upon a time, using 6 1TB drives. I can save you a lot of grief by suggesting that you don't think about this any further. Boy is it slow. And extremely unreliable. And slow. Don't even do it for backups. Did I say it was slow?
Steve ---------------------------------------------------------------------------- Steve Thompson E-mail: smt AT vgersoft DOT com Voyager Software LLC Web: http://www DOT vgersoft DOT com 39 Smugglers Path VSW Support: support AT vgersoft DOT com Ithaca, NY 14850 "186,300 miles per second: it's not just a good idea, it's the law" ----------------------------------------------------------------------------
Steve Thompson wrote:
On Tue, 15 Dec 2009, Scott Ehrlich wrote:
I have a client with a handful of USB drives connected to a CentOS box. I am charged with binding the USB drives together into a single LVM for a cheap storage data pool (10 x 1 TB usb drives = 10 TB cheap storage in a single mount point).
I tried doing this for fun once upon a time, using 6 1TB drives. I can save you a lot of grief by suggesting that you don't think about this any further. Boy is it slow. And extremely unreliable. And slow. Don't even do it for backups. Did I say it was slow?
Please qualify 'slow'. Was it dog slow, turtle-slow, snail-slow or slowaris slow?
On Wed, 16 Dec 2009, Chan Chung Hang Christopher wrote:
Steve Thompson wrote:
On Tue, 15 Dec 2009, Scott Ehrlich wrote:
I have a client with a handful of USB drives connected to a CentOS box. I am charged with binding the USB drives together into a single LVM for a cheap storage data pool (10 x 1 TB usb drives = 10 TB cheap storage in a single mount point).
I tried doing this for fun once upon a time, using 6 1TB drives. I can save you a lot of grief by suggesting that you don't think about this any further. Boy is it slow. And extremely unreliable. And slow. Don't even do it for backups. Did I say it was slow?
Please qualify 'slow'. Was it dog slow, turtle-slow, snail-slow or slowaris slow?
Slower than all of those. Top write speed I could ever achieve with a USB-2 interface and SATA drives was 20 MB/sec with a trailing wind, and usually half of that, with a single stream. I even tried USB-1 for more laughs; 1 MB/sec on a truly good day. With multiple writers, performance dropped so far as to be unusable (below 1 MB/sec). And we're talking mkfs times in _days_. The host was a CentOS 5.2 box, 32-bit.
Steve
Steve Thompson wrote:
On Wed, 16 Dec 2009, Chan Chung Hang Christopher wrote:
Steve Thompson wrote:
On Tue, 15 Dec 2009, Scott Ehrlich wrote:
I have a client with a handful of USB drives connected to a CentOS box. I am charged with binding the USB drives together into a single LVM for a cheap storage data pool (10 x 1 TB usb drives = 10 TB cheap storage in a single mount point).
I tried doing this for fun once upon a time, using 6 1TB drives. I can save you a lot of grief by suggesting that you don't think about this any further. Boy is it slow. And extremely unreliable. And slow. Don't even do it for backups. Did I say it was slow?
Please qualify 'slow'. Was it dog slow, turtle-slow, snail-slow or slowaris slow?
Slower than all of those. Top write speed I could ever achieve with a USB-2 interface and SATA drives was 20 MB/sec with a trailing wind, and usually half of that, with a single stream. I even tried USB-1 for more laughs; 1 MB/sec on a truly good day. With multiple writers, performance dropped so far as to be unusable (below 1 MB/sec). And we're talking mkfs times in _days_. The host was a CentOS 5.2 box, 32-bit.
Kudos to Steve for proving that USB2's 480mbits/sec is really just a sham.
Now I wonder if you can daisy chain IEEE1394 devices...or try out eSATA...:-P
On 12/16/2009 9:34 AM, Chan Chung Hang Christopher wrote:
Steve Thompson wrote:
On Wed, 16 Dec 2009, Chan Chung Hang Christopher wrote:
Steve Thompson wrote:
On Tue, 15 Dec 2009, Scott Ehrlich wrote:
I have a client with a handful of USB drives connected to a CentOS box. I am charged with binding the USB drives together into a single LVM for a cheap storage data pool (10 x 1 TB usb drives = 10 TB cheap storage in a single mount point).
I tried doing this for fun once upon a time, using 6 1TB drives. I can save you a lot of grief by suggesting that you don't think about this any further. Boy is it slow. And extremely unreliable. And slow. Don't even do it for backups. Did I say it was slow?
Please qualify 'slow'. Was it dog slow, turtle-slow, snail-slow or slowaris slow?
Slower than all of those. Top write speed I could ever achieve with a USB-2 interface and SATA drives was 20 MB/sec with a trailing wind, and usually half of that, with a single stream. I even tried USB-1 for more laughs; 1 MB/sec on a truly good day. With multiple writers, performance dropped so far as to be unusable (below 1 MB/sec). And we're talking mkfs times in _days_. The host was a CentOS 5.2 box, 32-bit.
Kudos to Steve for proving that USB2's 480mbits/sec is really just a sham.
Now I wonder if you can daisy chain IEEE1394 devices...or try out eSATA...:-P _______________________________________________ CentOS mailing list CentOS@centos.org http://lists.centos.org/mailman/listinfo/centos
Any host based technology won't get you half of the claimed speed with any kind of reliability. I don't think ti will ever really outrun something like SATAII or SAS. What makes it funnier is Intel is saying this will make external RAID on USB possible...just keep in mind FRIAD and that's what USB RAID really is.
Scott Ehrlich wrote:
I have a client with a handful of USB drives connected to a CentOS box. I am charged with binding the USB drives together into a single LVM for a cheap storage data pool (10 x 1 TB usb drives = 10 TB cheap storage in a single mount point).
How about eSATA? Surely an eSATA enclosure for 10 drives won't be more expensive than ten individual usb enclosures?!
The next fun piece is how to incorporate that storage space into an existing Active Directory structure to apply AD acls for limited access.
AD does not have acls. NTFS does. The closet things to NTFS acls in UNIX is nfs4 acls. That you can get with ZFS. I suggest that you give OpenSolaris a shot instead. Or you can be one of the testers for ntfs-3g's acl implementation...
I'd rather not use Samba, as that is its own infrastructure and maintains its own credentials database.
Have you ever used winbind? It maps AD credentials to POSIX credentials.
What are my best options?
Stuff not provided by Centos/RHEL at the moment.
On 12/15/2009 7:48 AM, Scott Ehrlich wrote:
I have a client with a handful of USB drives connected to a CentOS box. I am charged with binding the USB drives together into a single LVM for a cheap storage data pool (10 x 1 TB usb drives = 10 TB cheap storage in a single mount point).
(snip)
What are my best options?
Um, don't? Like other people said, go with eSATA, hopefully hooked up to a 4-drive or 8-drive enclosure (or even a 10-drive enclosure).
Alternately, go with an external SAS storage rack that supports both SAS / SATA drives. A SAS card for PCIe is fairly inexpensive ($200?) and the external enclosures are probably going to be (but not certainly) better made then inexpensive SATA enclosures.
The big problem with USB is that it only supports about 25MB/s per port, which means that it's going to be very very slow. Modern hard drives can push 50-80MB/s easily.
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Chan Chung Hang Christopher -
Eero Volotinen -
Joseph L. Casale -
Keith Keller -
Kristopher Kane -
nate -
Nicholas -
Scott Ehrlich -
Steve Thompson -
Thomas Harold -
Toby Bluhm -
William Warren