You do realize that my posting this, you are causing a moderator to waste a precious point to moderate you down, thus lowering the available number of points to moderate down the post which you are requesting be moderated. You are fighting against yourself.
Don't worry, chances are if you think it should be moderated down, someone with moderator status will too and will take care of it.
To make a short story long, stop posting stupid comments like:
We decided on Exchange because of the group scheduling. There isn't a viable alternative for "groupware" in the open-source community. If we were just looking for e-mail, it would have been a no-brainer to setup a nice Linux box and forget about it.
That is one of the funniest things I've heard about in a long time. You aren't coming near my subnet!
Let this be a lesson to look before you leap, especially when the leap is right, smack dab in the middle of a pile of sh^h^h^h beta software from Microsoft.
I am grateful that there are code monkeys out there that enjoy low-level programming. We are forever indebted to them, but . ..
I don't thing my company is going to pay me to write device drivers or hack the kernel. They need rapidly developed, quality apps. Delphi has been an excellent tool to accomplish this, even with the limitations inherent to Win32.
Delphi for Linux would help immensely in the push to the desktop and I would be the first one on my block to purchase it.
I just went to one of Phil's lectures here at MIT and he told us that was the one that negotiated the open sourcing of AOLServer. He said that the negotiations took place on Instant Messenger.
I was under the impression that all MS software was essentially a beta version. They just happen to have an extremely large test group that is willing to pay money for the privilege of testing it.
1) RAID 0 can either be striping, doing writes a chunk at a time to each disk in the stripe set, or concatenation, which is slapping multiple disks together to make one big virtual disk and then writing so you fill up the disks in sequence.
You are correct. I wasn't trying to write a complete discourse on RAID, just point out details relevant to the original post. My mistake for intimating that it was only striping.
2) RAID 5 can only tolerate losing 1 disk in its set. The volume can continue in "degraded" mode where for every read off of the volume, the system has to calculate the parity bit to make up for the lost disk. If you throw in one hot spare you could lose 2 disks total. (The hot spare takes over for the 1st disk to go..the volume needs a period of time to sync the data/parity to it, but then continues normally. You can then lose 1 more disk..this will put you in "degraded" mode.)
You will have to re-read my post as none of what you said contradicts me. I made the point that, with a hot spare, not until the 3rd disk fails will you be unable to use the system. Just a matter of how you phrase it, but the point is, you can lose 2 disks and still function. Granted, the performance is degraded by using the parity information.
3) I'm not sure where you've gotten the impression that RAID 5 is excellent for performance. Calculating parity bits for *every* read is the antithesis of performance. RAID 5 (or "poor man's mirroring") is good for systems that need the data redundancy but cannot afford the cost of doubling their disk usage for mirroring. However, no compentent SysAdmin would use the terms "performance" and "RAID 5" in the same sentence.
RAID 5, according to everything I have been able do read on the subject, does give you increased performance over RAID 1, especially when reading data. Essentially, it is like reading from a RAID 0 striped set. Writing data does take some more time due to the parity bits as you mentioned. I believe it was pointed out elsewhere that file servers are perfect for RAID 5 due the the increase in performance coupled with the data redundancy but Database servers would not function very well with RAID 5. I was merely contradicting the previous statement that a file server should use RAID 5 because of the lack of performance. To repeat another poster, if money wasn't an issue, we'd all have RAID 0/1.
The only performance benefit you might get from RAID 1 is that it is SCSI. The file exists on each drive and must be read from the primary drive. In order to appreciate any performance gain on reads in a RAID you must be reading from multiple sources simultaneously.
I said *next* best peforming RAID level, as in it will do 50% worse than RAID 0. (You do know you can do RAID 1 with an arbirary number of drives right? It's called RAID 1+0)
RAID 0/1 requires 4 disks and it is configured with 1 pair of disks (the RAID 1 part) mirroring a striped pair of disks (the RAID 0 part).
RAID 5 will do 50% worse again than RAID 1 for the same number of drives.
That is just plain wrong. RAID 1 is mirroring. Because the controller has to write the same data to two disks, there is a performance decrease.
RAID 0 is just a striped pair. The data is spread out over two disks so that reading and writing data can be distributed over both disks.
RAID 5 is the addition of parity information to a striped set. The data and parity info is spread out over all the drives with the parity info never residing on the same drive as any other part of the file.
If you go to read file 1, the RAID controller will read part 1 from drive #1 and part 2 from drive #2 simultaneously. Read performance from RAID 5 is essentially the same as RAID 0.
If you want to write file 1, the RAID controller will write part 1 to drive #1, part 2 to drive #2 and the parity information to drive #3. This is slower than RAID 0 because of the parity information but still faster that RAID 1 because you are not writing the entire file to two places. You are splitting up the write duties to 2 of the drives and taking some overhead time to calculate and write the parity information.
Only if you have a server where performance isn't much of an issue, e.g. a file server, should you consider RAID 5.
RAID 5 is excellent for applications where you need performance and data integrity. Add a hot spare to the array and you will have to have 3 disks fail simultaneously to take you down!
Read a little bit more about RAID. It can be complicated but it'll be nice to know. Good luck.
btw, that's doing RAID 0 - if you want some fault tolerance, and go to the next highest performing RAID level, RAID 1, plan on doubling that.
RAID 1 is mirroring and therefore gives no performance advantage. In fact, there is a slight performance hit for the overhead of writing the same data twice, once for each disk.
RAID 5 is a good compromise between data integrity and speed. You should really go for at least 4 disks and more if you can afford it as the % of space lost to parity information goes down as you increase the number of drives.
I needed a good laugh. Now my wife want's to know why I am laughing out loud at the computer.
Bzzzzzzzzzzzzzzzzzt! Sorry, please try again
on
Digital VCRs
·
· Score: 1
Apatch(sic) just to do MLPPP? how lame. That comes stock with win9x.
It didn't appear until OSR2 and that wasn't a user upgradable release so Win98 is the first Win9x variant with the ability to have more than one IP address per machine.
The purpose of it all is to accomplish a task. If RPN floats your boat, use an HP. If you're more of an algebraic dude, get a TI. The last thing we need is an HP/TI holy war. It's a calculator, not a religion.
Just remember, friends don't let friends use Casios.
Slashdot Mirror
Don't worry, chances are if you think it should be moderated down, someone with moderator status will too and will take care of it.
To make a short story long, stop posting stupid comments like:
Well I'm got a B.S. in Zoology and I hooked up my Mandrake box to my toaster.
Now I have a crontab make me some nice toast every morning. I just have to get Mod-Jam working so I can stop eating dry toast.
We decided on Exchange because of the group scheduling. There isn't a viable alternative for "groupware" in the open-source community. If we were just looking for e-mail, it would have been a no-brainer to setup a nice Linux box and forget about it.
Let this be a lesson to look before you leap, especially when the leap is right, smack dab in the middle of a pile of sh^h^h^h beta software from Microsoft.
It would probably cause an access violation. I don't believe Bill has discovered pipes yet.
That was Fats Domino (the singer of the subject song, not the pervert).
My pre-order will be in just as soon as they will take my money.
I am grateful that there are code monkeys out there that enjoy low-level programming. We are forever indebted to them, but . . .
I don't thing my company is going to pay me to write device drivers or hack the kernel. They need rapidly developed, quality apps. Delphi has been an excellent tool to accomplish this, even with the limitations inherent to Win32.
Delphi for Linux would help immensely in the push to the desktop and I would be the first one on my block to purchase it.
I just went to one of Phil's lectures here at MIT and he told us that was the one that negotiated the open sourcing of AOLServer. He said that the negotiations took place on Instant Messenger.
I made a sandwich.
Let's see an Alpha running at the equivalent of a Celeron 300a for under $50.
I was under the impression that all MS software was essentially a beta version. They just happen to have an extremely large test group that is willing to pay money for the privilege of testing it.
You are correct. I wasn't trying to write a complete discourse on RAID, just point out details relevant to the original post. My mistake for intimating that it was only striping.
You will have to re-read my post as none of what you said contradicts me. I made the point that, with a hot spare, not until the 3rd disk fails will you be unable to use the system. Just a matter of how you phrase it, but the point is, you can lose 2 disks and still function. Granted, the performance is degraded by using the parity information.
RAID 5, according to everything I have been able do read on the subject, does give you increased performance over RAID 1, especially when reading data. Essentially, it is like reading from a RAID 0 striped set. Writing data does take some more time due to the parity bits as you mentioned. I believe it was pointed out elsewhere that file servers are perfect for RAID 5 due the the increase in performance coupled with the data redundancy but Database servers would not function very well with RAID 5. I was merely contradicting the previous statement that a file server should use RAID 5 because of the lack of performance. To repeat another poster, if money wasn't an issue, we'd all have RAID 0/1.
The only performance benefit you might get from RAID 1 is that it is SCSI. The file exists on each drive and must be read from the primary drive. In order to appreciate any performance gain on reads in a RAID you must be reading from multiple sources simultaneously.
RAID 0/1 requires 4 disks and it is configured with 1 pair of disks (the RAID 1 part) mirroring a striped pair of disks (the RAID 0 part).
- RAID 5 will do 50% worse again than RAID 1 for the same number of drives.
That is just plain wrong. RAID 1 is mirroring. Because the controller has to write the same data to two disks, there is a performance decrease.RAID 0 is just a striped pair. The data is spread out over two disks so that reading and writing data can be distributed over both disks.
RAID 5 is the addition of parity information to a striped set. The data and parity info is spread out over all the drives with the parity info never residing on the same drive as any other part of the file.
Look at the following diagram (fig 1.1)
drive #1 | drive #2 | drive #3
-------------------------------
file 1.1 | file 1.2 | file1.p (parity information)
file 2.p | file 2.1 | file 2.2
file 3.2 | file 3.p | file 3.1
If you go to read file 1, the RAID controller will read part 1 from drive #1 and part 2 from drive #2 simultaneously. Read performance from RAID 5 is essentially the same as RAID 0.
If you want to write file 1, the RAID controller will write part 1 to drive #1, part 2 to drive #2 and the parity information to drive #3. This is slower than RAID 0 because of the parity information but still faster that RAID 1 because you are not writing the entire file to two places. You are splitting up the write duties to 2 of the drives and taking some overhead time to calculate and write the parity information.
- Only if you have a server where performance isn't much of an issue, e.g. a file server, should you consider RAID 5.
RAID 5 is excellent for applications where you need performance and data integrity. Add a hot spare to the array and you will have to have 3 disks fail simultaneously to take you down!Read a little bit more about RAID. It can be complicated but it'll be nice to know. Good luck.
RAID 1 is mirroring and therefore gives no performance advantage. In fact, there is a slight performance hit for the overhead of writing the same data twice, once for each disk.
RAID 5 is a good compromise between data integrity and speed. You should really go for at least 4 disks and more if you can afford it as the % of space lost to parity information goes down as you increase the number of drives.
Nope, emacs isn't better than windows. Vi, on the otherhand, IS better than windows.
I needed a good laugh. Now my wife want's to know why I am laughing out loud at the computer.
It didn't appear until OSR2 and that wasn't a user upgradable release so Win98 is the first Win9x variant with the ability to have more than one IP address per machine.
Stuff like that makes me proud to be a geek.
It may be a compromise but only a small one. The 48 has algebraic entry available and was quite easy to access, just one key press and you were there.
The purpose of it all is to accomplish a task. If RPN floats your boat, use an HP. If you're more of an algebraic dude, get a TI.
The last thing we need is an HP/TI holy war. It's a calculator, not a religion.
Just remember, friends don't let friends use Casios.
I have been know, when it's late at night and there is a full moon, to install new hardware in my system.
Not only can you, the installer since at least 5.1 recommends not formatting /home if you had a previous install.
I stand in awe of your telepathic abilities. How I wish to know, as you do, the thoughts of the animals and plants around me.
Did the head of the other species give you this information or did you have to do your own research?
All in all, quite impressive.