I'm taking a look at the new machines and starting some tests... it may be a while before we figure out what do to with this much power! :D
Jimmy: I notice the Opteron box has 3 SCSI drives attached. sda is the system drive, then there are sdb and sdc... all are 30 GB, but only sda seems to be partitioned. Is this as it should be, or was there supposed to be a RAID setup? I don't remember...
-- brion vibber (brion @ pobox.com)
Brion Vibber wrote:
Jimmy: I notice the Opteron box has 3 SCSI drives attached. sda is the system drive, then there are sdb and sdc... all are 30 GB, but only sda seems to be partitioned. Is this as it should be, or was there supposed to be a RAID setup? I don't remember...
Those should be 36GB each.
This should be a RAID 5 array, 2+1, for a total logical volume of whatever, 72Gb-ish I guess?
Upon closer inspection, though, it looks like I've made a slight mistake.
LSI 20320 1 Channel U320 SCSI Controller is what I ordered.
http://www.lsilogic.com/products/ultra320_host_bus_adapters/lsi20320rb.html
This card only supports RAID 0 or RAID 1.
For our immediate purposes, which do we want? Mirroring (safety) or striping (performance)?
I'm thinking, but correct me if I'm wrong, that we can have one of the other machines run a replicator, giving us safety, and then we can do striping on this machine for performance.
In the future, when geoffrin is healthy and is the primary, Jimbo the President of the Wikimedia Foundation, Inc. will call Jimbo the President of Bomis, Inc., and complain. Jimbo@Bomis is responsible for the error, so we'll make him pay for a new card!
--Jimbo
p.s. In any event, is it reasonble to suppose that I need to do something hardware wise to setup striping?
For our immediate purposes, which do we want?
Mirroring (safety) or
striping (performance)?
Safety i'd say. And as much ram as possible for speed. -- Gabriel Wicke
I also argue that Safety is more important.
--Optim
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On Sun, 01 Feb 2004 07:05:07 -0800, Jimmy Wales wrote:
I'm thinking, but correct me if I'm wrong, that we can have one of the other machines run a replicator, giving us safety, and then we can do striping on this machine for performance.
In the future, when geoffrin is healthy and is the primary, Jimbo the President of the Wikimedia Foundation, Inc. will call Jimbo the President of Bomis, Inc., and complain. Jimbo is responsible for the error, so we'll make him pay for a new card!
Or would it be possible to get a proper card before doing more testing?
On Feb 1, 2004, at 07:05, Jimmy Wales wrote:
This card only supports RAID 0 or RAID 1.
For our immediate purposes, which do we want? Mirroring (safety) or striping (performance)?
Safety safety safety safety!
Oh, and safety.
p.s. In any event, is it reasonble to suppose that I need to do something hardware wise to setup striping?
I suppose... did they give you any manuals with these things? :)
(Did I mention safety?)
The only thing about RAID mirroring with those drives is the size of the database; we haven't yet run the old revision compression so the db might not quite fit on 36 GB. Once that's done is ought to, though, if everything's dumped out of the db and dumped back in to a fresh InnoDB table space file.
-- brion vibber (brion @ pobox.com)
On Sun, 1 Feb 2004, Jimmy Wales wrote:
Upon closer inspection, though, it looks like I've made a slight mistake.
LSI 20320 1 Channel U320 SCSI Controller is what I ordered.
http://www.lsilogic.com/products/ultra320_host_bus_adapters/lsi20320rb.html
This card only supports RAID 0 or RAID 1.
As opposed to what other card?
I supposed you've forgotten linux has software RAID capability. I assure you, no RAID card within your budget will outperform the system processors even under load. While I generally recommend the use of hardware RAID, you don't have one of those in hand. So, unless you're going to go buy one *right now*, software RAID will do. (you *are* making backups, right?)
--Ricky
PS: Hardware RAID isn't magic. It can screw up your data too. My DPT SmartRaid IV spewed all over it's array a few weeks ago. The array was built several years ago. I now get the fun task of rebuilding '/' from all the numbers in '/lost+found'.
Ricky Beam wrote:
I supposed you've forgotten linux has software RAID capability. I assure you, no RAID card within your budget will outperform the system processors even under load. While I generally recommend the use of hardware RAID, you don't have one of those in hand. So, unless you're going to go buy one *right now*, software RAID will do. (you *are* making backups, right?)
O.k., that's a useful recommendation, even if I do feel like you're yelling at me. :-)
When I was at the colo this morning, I tried to setup the hardware RAID for safety, safety, safety as encouraged by everyone, but I failed. The LSI setup utility told me that the version of the firmware doesn't support RAID. Since the card itself is alleged (by the Internet) to support RAID, I'm guessing all I have to do is update the firmware, but I figured I'd come back home and research that since the machine is going to be running memtest86 overnight anyway.
RAID 5 via software RAID sounds better to me than straight mirroring using the hardware RAID, because 36GB isn't very joyful for us. 3 36GB drives will give us 72GB-ish logical space on a RAID 5 array, with safety as well.
I have not setup software RAID in some years, but presumably it isn't hard?
--Jimbo
On Mon, 2 Feb 2004, Jimmy Wales wrote:
Ricky Beam wrote:
I supposed you've forgotten linux has software RAID capability. I assure you, no RAID card within your budget will outperform the system processors even under load. While I generally recommend the use of hardware RAID, you don't have one of those in hand. So, unless you're going to go buy one *right now*, software RAID will do. (you *are* making backups, right?)
O.k., that's a useful recommendation, even if I do feel like you're yelling at me. :-)
Heh. That's not yelling. THIS IS YELLING YOU TWIT. *grin* If you check the archives (assuming it's in there), you'll see I was one of those in favor of hardware RAID. Software RAID is real easy to break. Hardware RAID, not so much -- you don't get direct access to the drives.
I have not setup software RAID in some years, but presumably it isn't hard?
It's not hard. And the modern tools (mdadm) make it even easier. The only problem is booting from RAID5. You'll need to create a boot partition that's RAID1 mirrored across all the drives in the array so you'll be able to boot if any drive fails. Then create the RAID5 rootfs. Rinse and repeat...
I'll dig up the raidtab.conf (whatever) from milkweed to show the madness. (attached)
--Ricky
On Sun, 2004-02-01 at 07:05, Jimmy Wales wrote:
In the future, when geoffrin is healthy and is the primary, Jimbo the President of the Wikimedia Foundation, Inc. will call Jimbo the President of Bomis, Inc., and complain.
I have an image of a man with a cell phone in each hand, one against each ear...
Carl Witty
wikitech-l@lists.wikimedia.org