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sas and scsi

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October 9, 2007 12:14:12 AM

hello,
i'm trying to decide which of the drives to get,
two 36GB SCSI ultra320 (ST336754LW) OR
two 36GB SAS drive (ST336754SS) ?
both by seagate 15K.4 36.7GB 8MB.

now, those two, either SAS or SCSI will be in Raid 0 and will run,
Vista, App's, and Media files.

can someone give me an advice what to buy?? (both same price!!)
the SAS or the SCSI??

and while you do, i will need a very relieble controler to raid them on asus extreme striker??
can someone give me a model no.??

tnx,

Oren.

More about : sas scsi

October 9, 2007 12:45:20 AM

A good controller will be expensive... why not buy some good SATA drives?
October 9, 2007 1:06:06 AM

yes that i know!
besides, expensive is relative.
can u direct me to something?
model no. , name, price? anything at all???
tnx again.
Related resources
October 9, 2007 1:57:18 AM

Stick with the main names
Areaca, 3ware, Adaptec, Promise

I personally have a Adaptec 3805 which suits my raid 5 needs. Didnt really research SCSI when i was buying mine though
October 9, 2007 3:09:16 AM

personally i would stick with a sas controller, because not only do you get an option of using 15k hdds, but you can also connect a "much" larger 7200 sata hdd for media storage. which would seem the way to go for something more balanced.

the reason for raid 0 may be questionable, if you dont have specific uses set aside for it (such as video editing). but that aside, for just storing media, a large inexpensive 7200 would seem to be the way to go (500+ GB for ~$100), as performance isnt essential for storage. and you may also be able to go instead with a single 15k sas hdd for the OS and applications, which is where performance really matters, bypassing raid 0 altogether. which will keep heat, noise levels, and power consumption down too. (youll need some form of active cooling for the 15k hdds)

however, if cost is a concern, it doesnt seem to be, but if it is at all, going with a u160 scsi controller, 15k scsi hdd, and terminated scsi cable off of ebay even, may save you a noticable amount of money. and youll get around the same performance as 15k sas, also depending on how old the 15k scsi hdd is. such as, if its an older 15k scsi hdd, even a 10k raptor is pretty comparable, for desktop uses anyhow.

a secondary suggestion, considering how much this is likely to end up costing if you do go with it, is to maybe look into instead getting a solid state disk. the $/GB is worse, but you dont need to bother with an additional controller either, which balances the cost out some.

since the main reasons for going with higher rpms are the reduced wait times from faster file accessing and locating, seconded by actual transfer performance of the data, having no wait times at all in that respect would seem even better, imo.
October 9, 2007 9:47:29 AM

how much faster will be one SSD drive instead of two 15K in raid 0??
October 9, 2007 10:55:47 AM

it depends on your intended uses. when it comes to the majority of applications and windows uses, access and seek time/performance will have a much more profound impact than increased STRs will.

such as, if you play games, youll practically reduce load times as much as possible (your cpu and such would begin to be a bottleneck more), and gameplay should be very smooth as a result too from a data accessing standpoint (similar to caching it entirely to system ram, as thats essentially what an ssd is, but its not volatile like ram is), whereas 2 15k's in raid 0 wont be much faster at all than a single 15k most times, and at other times theres no improvement at all to speak of over a single hdd.

from an absolute standpoint, the access times of an ssd will be less than .1ms, due to no moving parts needing to locate data. whereas a single 15k will have access times many times slower, around ~5ms, and a second 15k in raid 0 will have access time performance slightly slower still, due to needing to position multiple heads when finding data, instead of just one head, its not slowed enough to notice though, most likely. ~5ms is still faster than the ~8ms of a raptor, and much faster than the ~14ms of a 7200. PMR has managed to reduce the effective seek times of 7200s though, due to greatly increased density per platter, resulting in improved desktop performance, putting them closer to that of a raptor (the actual access and seek times are still the same speed though, due to using the same rpms and 3.5" platters, so it still takes the same amount of time to actually locate data, making fragmentation still a very bad thing for them, unlike raptors (higher rpms and smaller 2.5" platters), less so still for 15ks (also 2.5" platters) and not at all for ssds (no platters or rpms to worry about).

when it comes to STRs though, ssds are lower usually. maxing out at about 60MB/s for some current models, and over 100MB/s for other more expensive ones.

another plus is that they generate no noise, little to no heat, consume less power, and arent at risk of failure, again, due to no mechanical parts being able to be worn out, so they have a rated MTBF much higher than that of mechanical hdds too. the downside though, is they can be very expensive, no doubt, mainly due to them being a newer technology.
October 9, 2007 1:20:56 PM

I would definately recomend either the SAS or SSD. I see SCSI away in the not to distant future and the SAS controller would give more future options. Also as I think someone mentioned SAS controllers can also hook up SATA drives. I have the adaptec 31605 SAS card and love it. It is currently hooked up to 4-2.5" 10K RPM SAS drives and I get excellent sustained transfer rates for when I do my vidoe work. Since they are running 10K my access time is still decnt although it could be a little better.

I am still craving more speed though and will soon be converting to 8 SSD's in a RAID 0. Since the access time is vrirtually nothing I am hopefull this will add even more quickness to the system. If you do want to look at SSD drives take a look at the MTron units at DVNation. They are more expensive but are able to sustain around 90MB/s which very few other drives can at this point in time. You will pay a premium for the drives though since they arenew and fast. Also they top out at 32Gb so far so you may have to string a few together to get good storage space.
October 9, 2007 1:26:52 PM

shacharoren said:
hello,
i'm trying to decide which of the drives to get,
two 36GB SCSI ultra320 (ST336754LW) OR
two 36GB SAS drive (ST336754SS) ?
both by seagate 15K.4 36.7GB 8MB.

now, those two, either SAS or SCSI will be in Raid 0 and will run,
Vista, App's, and Media files.

can someone give me an advice what to buy?? (both same price!!)
the SAS or the SCSI??

and while you do, i will need a very relieble controler to raid them on asus extreme striker??
can someone give me a model no.??

tnx,

Oren.


I don't think that SAS or SCSI will effect your ability to run in a RAID 0. With that being said I would stick with SAS just because that's one less interface you have to deal with.

Like someone above me said as well I would stick with the well known RAID controllers. Adaptec is a good brand, it's also a common one.
Most of the ones I work with have been PERC 5/i or SERC 5/i. Both are from adaptec if I'm not mistaken. But that would be overkill if you just want to do a RAID 0.

Most motherboards now a days have an integrated low level RAID controller don't they? (0,1, and sometimes 5)
October 9, 2007 1:35:46 PM

Yes they do have RAID 0 but most onboard controllers wont do SAS. I think There was a review of controller cards on either toms or anandtech not to long ago. I believe they were sata controllers but it was still interesting to see the difference they make compared to the onboard controllers.
October 9, 2007 2:52:58 PM

shacharoren said:
hello,
i'm trying to decide which of the drives to get,
two 36GB SCSI ultra320 (ST336754LW) OR
two 36GB SAS drive (ST336754SS) ?
both by seagate 15K.4 36.7GB 8MB.

now, those two, either SAS or SCSI will be in Raid 0 and will run,
Vista, App's, and Media files.

can someone give me an advice what to buy?? (both same price!!)
the SAS or the SCSI??

and while you do, i will need a very relieble controler to raid them on asus extreme striker??
can someone give me a model no.??

tnx,

Oren.

Go SAS, you can always attach regular SATA drives to the controller for more storage as well as fast/expensive SAS drives for speed. SCSI is becoming outdated.
October 9, 2007 11:16:01 PM

ok, so let's see if i've got this right,
if i'm looking for a fast drive that will run OS and apps like, CS# and video editing software, and general windows use,
thses apps, including the OS is like 90% seek times and 10% write, meanning an SSD drive will be much better even for a single drive, and will give much better preformance than a 2 SAS in raid 0 will give me for the same purposes (OS use and apps)
in that case, a configuration of 2 SAS of 36GB and a controler will cost arond 800$, how much will be a 36GB SSD with a good transfer rate of MTron??
October 10, 2007 12:16:20 AM

some applications are heavily read/write dependant. mainly the ones that involve editing and transferring of large files, or constant hdd thrashing and almost nonstop accessing by an application (as a more extreme example that would benefit more), but again, most else will show little to no benefit from using raid 0.

heres a review of a 32GB mtron
http://www.anandtech.com/storage/showdoc.aspx?i=3064&p=...

browsing over the article i didnt see a price, but i can imagine it would be more or less close to the $800 youre already looking to spend, hopefully less though if anything.
October 10, 2007 12:52:19 AM

a 36gb SSD is like $300-400
October 10, 2007 12:54:55 AM

thats cool then, i looked over anandtech.coms user comments, someone on it said a 32GB was ~$850, when they were commenting about the 64GB SSDs. though i couldve misread that too..
October 10, 2007 1:13:53 AM

you said
"some applications ....nonstop accessing by an application"
can you give me examples?
let's take photoshop CS3 and Avid and adobe editing software,
can you tell about them?
will they need a fast read/write preformance?
October 10, 2007 1:23:59 AM

newegg says $300-400
October 10, 2007 7:01:57 AM

well, some examples of disk thrashing or nonstop accessing could be network based, such as a P2P filesharing client, or similar... where theres the 'potential' to have many different people accessing your raid array at the same time, most likely maxing out your network bandwidth if thats the case. the likelyhood of that taking a large toll on a hdd is small in my experience, but some other people may experience otherwise on a regular basis. another example is simply if theres a ton of copying over a lan, or just between hdds on your pc, maybe for the purposes of backing up data from the raid 0 array.

for photoshop and such, theres really only the need for raid 0 level performance, if the file sizes youre dealing with are at the very least a few hundred MB in size, or multi GB each even.... or if youre needing to manipulate/read/write many, many smaller files quickly even, hundreds or thousands of tiny files even (which is more or less like disk thrashing in this sense). for only a few smaller files, such as only a dozen or so 1KB+ sized files, raid 0 really isnt worth it. because a single current hdd is more than capable of handling that quickly.

also, as far as hundreds or thousands of tiny files are concerned (such as with an OS for example), faster access and seek times can help a lot here too, especially if the files are scattered on the hdd, cuz then you need to locate the files one at a time, ontop of actually taking the time to edit them (which is a primary reason raptors are still some of the fastest desktop sata hdds, even the oldest ones, their STRs arent the fastest anymore, but their access and seek times still are).

but, for those applications you mentioned, i would say they would see a fairly strong benefit from raid 0, as the file sizes youre dealing with will most likely be fairly large.

@skittle: i stand corrected. yeah, on newegg they range from $300 to $780, for the 32GB versions anyhow
http://www.newegg.com/Product/ProductList.aspx?Submit=E...
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