SCSI drives cost a lot more than SATA drives, do they really worth the dollar? I talked to two close friends worked in two hard drive makers, and they tell me there is not a big difference in performance, but SCSI drives are probably more reliable.
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SCSI drives cost a lot more than SATA drives, do they really worth the dollar? I talked to two close friends worked in two hard drive makers, and they tell me there is not a big difference in performance, but SCSI drives are probably more reliable.
SCSI drives are definitely faster than SATA drives, no question about that. The load they'll put on the CPU is also much lower. The only SATA drive that can come anywhere close to SCSI performance is the 74GB WD Raptor as it is 10K RPM and has command queuing. Still, a good 15K RPM SCSI drive will wipe the floor with the Raptor...
but 15K scsi is even more expensive...
I did some tests on mysql, on systems with 10K scsi and 7200rpm sata, there isn't much difference.
Depends what you call not much of a difference. using the WHT Unix bench that is around we got a score of 210 on a system with a 73GB SCSI drive and a score of 160 using a server with the same specs, except a 74GB Raptor instead of the SCSI drive. Did the benchmark you ran show you differences in performance for when multiple applications are requesting the disk at the same time, and was the benchmark even maxing out the drive, or was the CPU or RAM a bottleneck?Quote:
Originally posted by wm2100
but 15K scsi is even more expensive...
I did some tests on mysql, on systems with 10K scsi and 7200rpm sata, there isn't much difference.
In a web hosting environment I have seen massive increases in performance by using a SCSI drive.
Also, yes, 15K RPM drives are even more expensive. if you need the speed of a SCSI drive then the price difference is more than worth it. if you don't need it, and a SATA or IDE drive will fit your needs don't waste the money on a SCSI drive. if CPU/RAM are going to be your bottleneck then why pay for the more expensive drive, but more often than not, the bottleneck is IO, thus a lower speed drive may be cheaper, but it would also prevent you from utilizing all the server has to offer.
And where would one get the "WHT Unix bench"?
The lines are actually pretty blurred when comparing 7200 RPM SATA (with their 8MB cache) to a 10000 RPM SCSI. Probably a bit better with the SCSI but when you add in the cost factor, you pay dearly for that 'extra little bit' of speed. Stability wise and depending upon Manufacturers, I would say they are about the same.
15K scsi will be probably more than twice faster than 7200 sata, but at the end of the day, all drives are very slow compared to ram. Last time I checked, a 300GB scsi costs $900, with this money, I think is better to put 4 200GB sata drives in raid 10, and you still have $400 to buy 2GB of ram...
Then go with that option... I have found that disk IO is almost always the first bottleneck faced. if getting a SCSI drive prevents you from needing to get another server then it is worth it. I have seen many cases where people complain about speed on a server and they get another server to offload some things when those people would be much better off just upgrading to a SCSI drive and that would have been much cheaper than getting an entirely new server.Quote:
Originally posted by wm2100
15K scsi will be probably more than twice faster than 7200 sata, but at the end of the day, all drives are very slow compared to ram. Last time I checked, a 300GB scsi costs $900, with this money, I think is better to put 4 200GB sata drives in raid 10, and you still have $400 to buy 2GB of ram...
You get the correct tool for the job, simple as that. There are cases where there is absolutely no reason for a SCSI drive and then there are cases where there is absolutely no reason to not go with a SCSI drive.
Karl makes a very good point.
Listen to him.
Karl's on a roll today. ;)
It's all about disk/file IO. If you don't want to be bottlenecked by IO to/from your drives on your server then you need to go with SCSI, all the other benefits like reliability and generally better warranties are just icing on the cake.
If you're just running a light server only running a fews apps with light IO, by all means stick with SATA drives and save some $$$.
Generally my loaded Dual 3Ghz Xeon web servers start peaking with writing/reading to the SCSI drives before they get close to maxing out their CPU's.
It's not about one being better than the other in all instances, it's about choosing the right one for the job (or server in this case).
Like others have stated, it depends on your application. If it's delivering streaming videos, Gigabytes of images or any other file type under heavy loads, then disk IO will be a concern. Otherwise, adding enough RAM to cache your files would be a faster and cheaper solution.
If your app is disk IO bound, I would recommend RAID 5 with 6 enterprise class SATA drives (1 being hot spare). This config can usually fit in 2U case. The key is in having multiple drives working together. More drives improve performance and reliability as well as increasing total disk capacity. The performance would be boosted by almost 5 times the speed of a single drive.
We went over this just a couple days ago:
http://www.webhostingtalk.com/showth...5&pagenumber=1
The second to last post by dzeanah sums it up quite well.
We need to look deeper. What is the advantage of SCSI?
Rotation speed? not much faster. SCSI can reorder commands to optmize access, but with NCQ, SATA disk can do the same. In a web server envrionment, you are reading small files and send them over the network all the time. More memory is the solution, as the system can buffer more data in the core...
Database is different, database access tends to be more random, but in my tests, I see very little advantage of using scsi.
In a recent thread called "Old Servers"
http://www.webhostingtalk.com/showth...5&pagenumber=4
I attempted to show how an old PIII could hold up to what is called "today's hardware". The significant difference is SCSI Drive. Here is some emperical data to demonstrate the difference between SCSI and IDE.
Athlon 64 3000+
512MB Ram
80GB IDE
Windows 2003 Standard
CPU Mark = 395.2
Memory Mark = 369.0
Disk Mark = 115.8
PassMark = 196.3
******************************
******************************
Dual PIII 1.133 GHz
1024 MB PC133 ECC
3 X 36 SCSI RAID
Windows 2003 Enterprise
CPU Mark 379.7
Memory Mark 200.4
Disk Mark 208.2
PassMark Rating 180.2
I think there is a difference between SATA and IDE.
SATA can do 1.5gbs, newer SATA drive can do NCQ.
Don't you guys get it? His benchmarks are conclusive... It doesn't matter what experiences you've had, its not deep enough... SCSI has no advantages anymore, who cares how long its been around, its outdated and useless... Spindle speed? bah... performance and value supercede everything else for ALL applications...
iowait - iobahumbug... SATA 0wn$ j00!!! Now you industry guys have to understand, wm2100 is smarter than you, and he knows what's the best hardware for your application... AMD/SATA.. What application? It doesn't matter, its better because anandtech and tomshardware say so! Real world experience doesn't count because you can't read it on paper or in articles... So it doesn't exist unless its in an article somewhere...
Dude take it from him, his friends work for a couple of hardware manufacturers, that should be credible enough for you to know SCSI sucks and there's no real justification for cost.. Reliability? Pshhh I can buy 3 SATA's for the price of one SCSI. Who cares how long it takes to fix them... when they go down.. you can buy 3 more of hdd's!!! It doesn't matter if you have 100 servers, you can buy 3x the hdd space! Performance? his tests are conclusive and final... Just like his other conclusive analysis... Semprons > Xeons for ALL applications, no matter what the situation...
Ya'll are just ignorant...
Quote:
Semprons > Xeons for ALL applications, no matter what the situation...
Ya'll are just ignorant....
Little bit of self contradiction there eh?
Quote:
Originally posted by ikeo
Don't you guys get it? His benchmarks are conclusive... It doesn't matter what experiences you've had, its not deep enough... SCSI has no advantages anymore, who cares how long its been around, its outdated and useless... Spindle speed? bah... performance and value supercede everything else for ALL applications...
iowait - iobahumbug... SATA 0wn$ j00!!! Now you industry guys have to understand, wm2100 is smarter than you, and he knows what's the best hardware for your application... AMD/SATA.. What application? It doesn't matter, its better because anandtech and tomshardware say so! Real world experience doesn't count because you can't read it on paper or in articles... So it doesn't exist unless its in an article somewhere...
Dude take it from him, his friends work for a couple of hardware manufacturers, that should be credible enough for you to know SCSI sucks and there's no real justification for cost.. Reliability? Pshhh I can buy 3 SATA's for the price of one SCSI. Who cares how long it takes to fix them... when they go down.. you can buy 3 more of hdd's!!! It doesn't matter if you have 100 servers, you can buy 3x the hdd space! Performance? his tests are conclusive and final... Just like his other conclusive analysis... Semprons > Xeons for ALL applications, no matter what the situation...
Ya'll are just ignorant...
Hahaha, now that was good. :-)
This is the first time I've ever heard someone saying SCSI sucks :D
SCSI drives definitely are better but the price/performance makes it questionable. Just want to point out that this test compares RAID of 3 SCSI drives against a single IDE drive. RAID-0 or 5 would be faster even if the other system had SCSI drive in it.Quote:
Originally posted by PSFServers
In a recent thread called "Old Servers"
http://www.webhostingtalk.com/showth...5&pagenumber=4
I attempted to show how an old PIII could hold up to what is called "today's hardware". The significant difference is SCSI Drive. Here is some emperical data to demonstrate the difference between SCSI and IDE.
Athlon 64 3000+
512MB Ram
80GB IDE
Windows 2003 Standard
CPU Mark = 395.2
Memory Mark = 369.0
Disk Mark = 115.8
PassMark = 196.3
******************************
******************************
Dual PIII 1.133 GHz
1024 MB PC133 ECC
3 X 36 SCSI RAID
Windows 2003 Enterprise
CPU Mark 379.7
Memory Mark 200.4
Disk Mark 208.2
PassMark Rating 180.2
This wasn't supposed to be an equal benchmark, he was trying to prove that his server could hold its own against the "latest" gear.
Like the others said, you will hit bottleneck with the HD way before CPU.
Having superfast CPU's with IDE is like.....installing a 500hp engine with a 3-speed automatic, or having a 20 inch LCD connected to a 8MB video card.
some of you guys are just close minded.
Look, SCSI or SATA, the physics is the same, rotating magnetic disk, SCSI has 10K rpm, most SATA has 7200RPM. but they are both horribly slow in seek time, around milli seconds.
The benchmark about athlon 64 3000+ and two pentium 3 1.3GHZ is not convincing. Two p3 1.3GHZ has the same CPU power of a 2GHZ athlon or 3GHZ p4. Just look at Pentium M, which is essentially P3, a 2GHZ PM beats P4 3.6GHZ in most benchmarks. INTEL has played the GHZ game and created 33 pipestage suckers, while P3 has less than 12 stages.
SCSI can queue commands, simply because it has additional circuits and logic. However, with a raid controller, it achieves the same functionality, for example, the 3ware controller I have has 128MB of memory, and does a lot of cache and command queue to reorder access.
SCSI is a share bus with around 300MB/s bandwidth total, no matter how many drives you add.
with SATA, you can combine 12 drives, each on independent SATA link, the total bandwidth will be higher than the SCSI.
2 P3 at 1.13 GHZ is about the same CPU power of a 3.2GHZ p4. You can run some CPU benchmarks to show it. Unlike P4 (which is to be terminated by INTEL soon), P3 is an efficient architecture. In fact, INTEL's Pentium M and next generation of servers will be based on P3, with lower frequency but higher performance.
Then comes to disk performance, 3 scsi and a raid controller will of course beat a single IDE.
Then the memory, I am not sure 512mB DDR is better than 1GB pc133, especially if the benchmark is memory hungry.
Quote:
Originally posted by PSFServers
In a recent thread called "Old Servers"
http://www.webhostingtalk.com/showth...5&pagenumber=4
I attempted to show how an old PIII could hold up to what is called "today's hardware". The significant difference is SCSI Drive. Here is some emperical data to demonstrate the difference between SCSI and IDE.
Athlon 64 3000+
512MB Ram
80GB IDE
Windows 2003 Standard
CPU Mark = 395.2
Memory Mark = 369.0
Disk Mark = 115.8
PassMark = 196.3
******************************
******************************
Dual PIII 1.133 GHz
1024 MB PC133 ECC
3 X 36 SCSI RAID
Windows 2003 Enterprise
CPU Mark 379.7
Memory Mark 200.4
Disk Mark 208.2
PassMark Rating 180.2
I agree with you that the max bandwidth of 1 SCSI channel is not capable of handling the theoretical max throughput from say fifteen 15K rpm drives but the SCSI RAID cards usually have multiple channels to use and most people would not put so many on 1 channel. I would use SATA RAID myself because of overall cost effectiveness but I must admit that nothing beats a set of 15K rpm drives especially for apps that heavily access data that cannot be buffered. I have not seen any SATA drives that are 15K out yet.Quote:
Originally posted by wm2100
SCSI is a share bus with around 300MB/s bandwidth total, no matter how many drives you add.
with SATA, you can combine 12 drives, each on independent SATA link, the total bandwidth will be higher than the SCSI.
Good to know that Intel is favoring P3 architecture. Thanks for the info.
Hello, interesting thread, am currently building a server for some of my sites which i am going to colo and would be interested to see if what i am doing is worth it it.
The main system is dual 1g p3, 4gb ecc reg 133 ram, the mb has dual ultra 160 channels on which i will have 2x18gb ultra160 drives in sw raid 0 these will be for mysql partition and most probably be xfs file system.
To the system i have added an adaptec 1205sa sata controller with 2x 160gb wd cavier re (raid edition) drives which will have main os patition in sw raid1 ext3 plus home parition in sw raid0 reisrfs and a backup partition in sw raid1 ext3.
Question is will gain anything by putting mysql on scsi drives? from what i have read i should get performance increase and of course bit more reliability.
The other question is what are best/ most reliable sata drives for server?
cheers
Are you asking for an opinion or giving us a lecture ... i thought you wanted opinion to start off but now you seem to be correcting everyone with all that knowledge you gained in the last 18 hours.
was that directed at me?Quote:
Originally posted by RazorBlue - Dan
Are you asking for an opinion or giving us a lecture ... i thought you wanted opinion to start off but now you seem to be correcting everyone with all that knowledge you gained in the last 18 hours.
Nope :) WHT's AMD expert...
Quote:
Originally posted by riverpast
Like the others said, you will hit bottleneck with the HD way before CPU.
Having superfast CPU's with IDE is like.....installing a 500hp engine with a 3-speed automatic, or having a 20 inch LCD connected to a 8MB video card.
Most top fuel drag cars have 3 speed automatics ;) - but we know what you were trying to say.
Look at price/performace
4x10k RPM 74GB Raptors SATA - ~$750
1x15k RPM 147GB SCSI - ~$800
With the SATA you get redundancy and speed (RAID 10) for a lower cost, however, increased heat dissipation and more space taken up. Hardware RAID controllers are expensive for both, and would take about the same CPU load. Personally, I'd agree with some people in this community being closed minded. Yes, SCSI is a better technology, but it is expensive and is starting to make less and less sense as time goes on.
Dude, you picked a 15,000 RPM drive to compare against a SATA. Get real.Quote:
Originally posted by 2uantuM
Look at price/performace
4x10k RPM 74GB Raptors SATA - ~$750
1x15k RPM 147GB SCSI - ~$800
With the SATA you get redundancy and speed (RAID 10) for a lower cost, however, increased heat dissipation and more space taken up. Hardware RAID controllers are expensive for both, and would take about the same CPU load.
I feel a good SCSI is a 10 year drive. Just get them used from a 3 year off lease deal and pay $1/GB. SCSI's are usually RAID-ed anyway, what do you have to lose.
You guys can go on, and on about SATA, but it ain't **** compared to SCSI. Period. End of Paragraph. Moses has spoken from the mountain top.
Ok :)Quote:
Originally posted by RazorBlue - Dan
Nope :) WHT's AMD expert...
Still does not answer my question but i think i know the answer that i will make me happy and that is that i have compromise between 2, scsi for task that it is suited too plus cost effectiveness of sata for os and storage.
Againt 4 SATA drives, not one. And really, you could go Maxtor MaxLine III's (250GB, 16MB Cache, $100) and get 8 of them, RAID-10. You can tell me all day that SCSI is a better technology, but from a price/performance standpoint, it makes no sense at all. Moses (heh), I'd feel more comforted that I have 4 redundant drives with a few year warranty on each than 1 ten year. But that's just meQuote:
Dude, you picked a 15,000 RPM drive to compare against a SATA. Get real.
I feel a good SCSI is a 10 year drive. Just get them used from a 3 year off lease deal and pay $1/GB. SCSI's are usually RAID-ed anyway, what do you have to lose.
You guys can go on, and on about SATA, but it ain't **** compared to SCSI. Period. End of Paragraph. Moses has spoken from the mountain top.
Besides, I'm sure your customers would feel very comforted that you're using "used" 3 year old scsi drives off of ebay.
seems to me that wm2100 has been disabled an resurfaced as Opteron4pQuote:
Originally posted by RazorBlue - Dan
Nope :) WHT's AMD expert...
If they are not the same, they are twin brothers :)
Any drive that works is PERFECT in a hot swap raid array. I'm not ashamed to use a 10 year old drive if I know it works. When the drive craps, I just throw it in the trash and put another one in the hot swap and there is ZERO down time.Quote:
Originally posted by 2uantuM
Besides, I'm sure your customers would feel very comforted that you're using "used" 3 year old scsi drives off of ebay.
Oh, yeah, I forgot, you are talking about DESKTOPS and not SERVERS. As far as your desktops go, we have had Bad 5 year warranty Seagate IDE and SATA from the factory. Many have crapped the first week on the server.
I would never run a server without RAID. So really it is a moot point. RAID is designed for hot swap replacement.
If it powers, spins and holds data and is on a redudent array, who cares! It is leased, it's my ***, not the customers.