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On Sat, 2002-11-16 at 17:19, John Andersen wrote:
On Friday 15 November 2002 08:13 am, Donald Grayson wrote:
We've been using the RAID 0 one at work and it's fabulous. Physically it takes up two drive bays and plugs into a standard Ultra66 IDE controller, the operating system and bios see it as a single drive. All the RAID functioning is done by the unit, so it's a really good setup for servers with a slow cpu.
What raid functions?
Raid 0 is just striping with no redundency. It essentially just concatenates two disks in such a way that losing either means you have lost everything. Your risk of loss just DOUBLED when you installed that.
You could have done as well (or better) with lvm in SuSE. At least all parts of a single file have a good chance of being on the remaining good drive after a failure.
The simple raid1 cards are really cheap these days and they take all the load off of the main processor.
Software raid has worked for me on ide drives but I only use raid 1 (mirroring) and only on two drives.
-- _________________________________________________ No I Don't Yahoo! And I'm getting pretty sick of being asked if I do. _________________________________________________ John Andersen / Juneau Alaska
My mistake, I meant they do RAID 1, not 0, and RAID 5. The unit we currently have is mirroring 80GB drives. As for why these are better than software RAID? Well, there's the offloading of the RAID management from the CPU to the unit itself. What CPU usage you asked? By it's very nature, a software RAID is running from your systems CPU. If all of the configuration, management and monitoring is being done by the controller and is totally transparent to the OS it is a Hardware RAID. Here's a link to benchmarks comparing the Accusys 7500 to a Highpoint PCI RAID card: http://www.motherboards.org/images/21/2002/1041_p4_1.jpg and the full review: http://www.motherboards.org/articlesd/hardware-reviews/1041_1.html Since this unit is self contained and OS transparent, it saves on space, leaves your PCI slots open for other things and uses one IDE cable and can be used on the standard IDE controller of almost every modern motherboard (they do have to be Ultra66 or higher). Although I'm not using it in this way, I believe it is bootable as well. Then there's little nicities like extremely easy installation, hot swapping, not having to crack open the case to swap the drives (yeah, some removeable drive bays can do the same but it's extra cost), automatic alarms to notify you if a drive fails and automatic rebuilding as soon as a new drive is installed. Don -- Check the headers for your unsubscription address For additional commands send e-mail to suse-linux-e-help@suse.com Also check the archives at http://lists.suse.com Please read the FAQs: suse-linux-e-faq@suse.com
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Very nice equipment ;)
wish I had the money for it to buy it now ;)
although it is tempting to eat only bread for a month to buy the thing ;)
No, serious , ..
I am certainly going to consider this piece of hardware, but unfortunately
at the moment it is to costly ... IThe server it is meant for is a home
build system used for our Unreal clan.
And as I am building it out of my own pocket I had to reduce some costs..
like for instance the RAID controller... I could easily put in a full blown
SCSI3 RaID- controller with appropriate disks .. but there was one cutback :
the cost :s
Thanks again for the replies!!!
Certainly bokmarked the page! who knows in the future ;)
regards
Chris
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Make money while you work !!!
http://www.degoo.com/index.php?refid=mersco
This is for real !!!
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----- Original Message -----
From: "Donald Grayson"
On Sat, 2002-11-16 at 17:19, John Andersen wrote:
On Friday 15 November 2002 08:13 am, Donald Grayson wrote:
We've been using the RAID 0 one at work and it's fabulous. Physically it takes up two drive bays and plugs into a standard Ultra66 IDE controller, the operating system and bios see it as a single drive. All the RAID functioning is done by the unit, so it's a really good setup for servers with a slow cpu.
What raid functions?
Raid 0 is just striping with no redundency. It essentially just concatenates two disks in such a way that losing either means you have lost everything. Your risk of loss just DOUBLED when you installed that.
You could have done as well (or better) with lvm in SuSE. At least all parts of a single file have a good chance of being on the remaining good drive after a failure.
The simple raid1 cards are really cheap these days and they take all the load off of the main processor.
Software raid has worked for me on ide drives but I only use raid 1 (mirroring) and only on two drives.
-- _________________________________________________ No I Don't Yahoo! And I'm getting pretty sick of being asked if I do. _________________________________________________ John Andersen / Juneau Alaska
My mistake, I meant they do RAID 1, not 0, and RAID 5. The unit we currently have is mirroring 80GB drives.
As for why these are better than software RAID? Well, there's the offloading of the RAID management from the CPU to the unit itself. What CPU usage you asked? By it's very nature, a software RAID is running from your systems CPU. If all of the configuration, management and monitoring is being done by the controller and is totally transparent to the OS it is a Hardware RAID.
Here's a link to benchmarks comparing the Accusys 7500 to a Highpoint PCI RAID card:
http://www.motherboards.org/images/21/2002/1041_p4_1.jpg
and the full review:
http://www.motherboards.org/articlesd/hardware-reviews/1041_1.html
Since this unit is self contained and OS transparent, it saves on space, leaves your PCI slots open for other things and uses one IDE cable and can be used on the standard IDE controller of almost every modern motherboard (they do have to be Ultra66 or higher). Although I'm not using it in this way, I believe it is bootable as well.
Then there's little nicities like extremely easy installation, hot swapping, not having to crack open the case to swap the drives (yeah, some removeable drive bays can do the same but it's extra cost), automatic alarms to notify you if a drive fails and automatic rebuilding as soon as a new drive is installed.
Don
-- Check the headers for your unsubscription address For additional commands send e-mail to suse-linux-e-help@suse.com Also check the archives at http://lists.suse.com Please read the FAQs: suse-linux-e-faq@suse.com
-- Check the headers for your unsubscription address For additional commands send e-mail to suse-linux-e-help@suse.com Also check the archives at http://lists.suse.com Please read the FAQs: suse-linux-e-faq@suse.com
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On Sunday 17 November 2002 04:48 am, Donald Grayson wrote:
As for why these are better than software RAID? Well, there's the offloading of the RAID management from the CPU to the unit itself. What CPU usage you asked? By it's very nature, a software RAID is running from your systems CPU.
Of course the above only matters if you have a high CPU utilization. Mine are (dual CPUs) are ideling along at 2% all the time.....
If all of the configuration, management and monitoring is being done by the controller and is totally transparent to the OS it is a Hardware RAID.
Yes, this is one of the BIG advantages....
Here's a link to benchmarks comparing the Accusys 7500 to a Highpoint PCI RAID card: (snipped)
Again, performance may prove to be one of biggest advantages, especially in a heavily loaded machine. But consider alternative points: 1 Placing a very expensive controller is an otherwise slow box may not improve real-world performance much 2 Applying a similar amount of funds to your MAIN CPU(s) may allow them to yield similar real-world performance with s cheaper ide-raid card OR with software raid 3 Applying those funds to the main processor and or memory also improves performance of many other aspects of performance and improves latency of other tasks that are not disk related 4 An infinant amount of funds applied to raid controllers will never allow you to get around the slow disk IO latency (slow in terms of disk-IO's HUGE contribution to overall data access cycle). 5 A relatively modest investment in main memory can make huge improvements in performance, especially on a busy server. Therefore, my experience over the years is that buying raid controllers for the ease of setup and convenience makes a great deal of sense if they are CHEAP, but allocating dollars elsewhere is more advantageous for overall system performance. I've purchased some of the high performance raid controllers (SCSI in my case) and saw minimal improvement in overall performance, easily outstripped by doubling main memory. - where's my spell checker... -- _________________________________________________ No I Don't Yahoo! And I'm getting pretty sick of being asked if I do. _________________________________________________ John Andersen / Juneau Alaska
participants (3)
-
Chris FitzGerald
-
Donald Grayson
-
John Andersen