Questions about SCSI

[TubsAlwaysWins]

Why are SCSI drives so expensive? Its like $50 for 300Gb!

[Sunshine1868]

I assume you mean SAS (Serial Attached SCSI)...

 

they are more expensive because of their application. 

Wikipedia gives great information as to the differences/advantages of SAS compared to SATA:

There is little physical difference between SAS and SATA.^[6]

• Systems identify SATA devices by their port number connected to the host bus adapter or by their universally unique identifier (UUID), while SAS devices are uniquely identified by their World Wide Name (WWN).
• SAS protocol provides for multiple initiators in a SAS domain, while SATA has no analogous provision.^[6]
• Most SAS drives provide tagged command queuing, while most newer SATA drives provide native command queuing.^[6]
• SATA uses a command set that is based on the parallel ATA command set and then extended beyond that set to include features like native command queuing, hot-plugging, and TRIM. SAS uses the SCSI command set, which includes a wider range of features like error recovery, reservations and block reclamation. Basic ATA has commands only for direct-access storage. However SCSI commands may be tunneled through ATAPI^[6] for devices such as CD/DVD drives.
• SAS hardware allows multipath I/O to devices while SATA (prior to SATA 2.0) does not.^[6] Per specification, SATA 2.0 makes use of port multipliers to achieve port expansion, and some port multiplier manufacturers have implemented multipath I/O using port multiplier hardware.
• SATA is marketed as a general-purpose successor to parallel ATA and has become common in the consumer market, whereas the more-expensive SAS targets critical server applications.
• SAS error-recovery and error-reporting uses SCSI commands, which have more functionality than the ATA SMART commands used by SATA drives.^[6]
• SAS uses higher signaling voltages (800–1,600 mV for transmit, and 275–1,600 mV for receive^{[clarification needed]}) than SATA (400–600 mV for transmit, and 325–600 mV for receive^{[clarification needed]}). The higher voltage offers (among other features) the ability to use SAS in server backplanes.^[6]
• Because of its higher signaling voltages, SAS can use cables up to 10 m (33 ft) long, whereas SATA has a cable-length limit of 1 m (3.3 ft) or 2 m (6.6 ft) for eSATA.^[6]
• SAS is full duplex, whereas SATA is half duplex. The SAS transport layer can transmit data at the full speed of the link in both directions at once, so a SCSI command executing over the link can transfer data to and from the device simultaneously. However, because SCSI commands that can do that are rare, and a SAS link must be dedicated to an individual command at a time, this is generally not an advantage.^[7]

 

 

TL;DR: SAS drives are for enterprise environments where more demanding hardware and protocols are required.

[brwainer]

And if you really meant SCSI and not SAS.... The high price is because noone makes SCSI drives anymore.

[Captain_WD]

~snip~

 

Hey there Tubs  

 

I believe this article would be useful for you: http://www.computerweekly.com/news/1362941/SATA-SCSI-and-SAS-Which-drive-is-right-for-your-storage-environment

 

@Sunshine1868 pretty much gave you the main differences between SAS and SATA drives. 

The shortest and simplest answer would be that SCSI drives are not that widely used besides every other difference.

 

Captain_WD.

[TubsAlwaysWins]

I assume you mean SAS (Serial Attached SCSI)...

 

they are more expensive because of their application. 

Wikipedia gives great information as to the differences/advantages of SAS compared to SATA:

There is little physical difference between SAS and SATA.^[6]

• Systems identify SATA devices by their port number connected to the host bus adapter or by their universally unique identifier (UUID), while SAS devices are uniquely identified by their World Wide Name (WWN).
• SAS protocol provides for multiple initiators in a SAS domain, while SATA has no analogous provision.^[6]
• Most SAS drives provide tagged command queuing, while most newer SATA drives provide native command queuing.^[6]
• SATA uses a command set that is based on the parallel ATA command set and then extended beyond that set to include features like native command queuing, hot-plugging, and TRIM. SAS uses the SCSI command set, which includes a wider range of features like error recovery, reservations and block reclamation. Basic ATA has commands only for direct-access storage. However SCSI commands may be tunneled through ATAPI^[6] for devices such as CD/DVD drives.
• SAS hardware allows multipath I/O to devices while SATA (prior to SATA 2.0) does not.^[6] Per specification, SATA 2.0 makes use of port multipliers to achieve port expansion, and some port multiplier manufacturers have implemented multipath I/O using port multiplier hardware.
• SATA is marketed as a general-purpose successor to parallel ATA and has become common in the consumer market, whereas the more-expensive SAS targets critical server applications.
• SAS error-recovery and error-reporting uses SCSI commands, which have more functionality than the ATA SMART commands used by SATA drives.^[6]
• SAS uses higher signaling voltages (800–1,600 mV for transmit, and 275–1,600 mV for receive^{[clarification needed]}) than SATA (400–600 mV for transmit, and 325–600 mV for receive^{[clarification needed]}). The higher voltage offers (among other features) the ability to use SAS in server backplanes.^[6]
• Because of its higher signaling voltages, SAS can use cables up to 10 m (33 ft) long, whereas SATA has a cable-length limit of 1 m (3.3 ft) or 2 m (6.6 ft) for eSATA.^[6]
• SAS is full duplex, whereas SATA is half duplex. The SAS transport layer can transmit data at the full speed of the link in both directions at once, so a SCSI command executing over the link can transfer data to and from the device simultaneously. However, because SCSI commands that can do that are rare, and a SAS link must be dedicated to an individual command at a time, this is generally not an advantage.^[7]

 

 

TL;DR: SAS drives are for enterprise environments where more demanding hardware and protocols are required.

 

And if you really meant SCSI and not SAS.... The high price is because noone makes SCSI drives anymore.

 

 

Hey there Tubs

 

I believe this article would be useful for you: http://www.computerweekly.com/news/1362941/SATA-SCSI-and-SAS-Which-drive-is-right-for-your-storage-environment

 

@Sunshine1868 pretty much gave you the main differences between SAS and SATA drives. 

The shortest and simplest answer would be that SCSI drives are not that widely used besides every other difference.

 

Captain_WD.

 

Ok thanks. I just have an old server that i want to put new drives if for a NAS

[TubsAlwaysWins]

I assume you mean SAS (Serial Attached SCSI)...

 

they are more expensive because of their application. 

Wikipedia gives great information as to the differences/advantages of SAS compared to SATA:

There is little physical difference between SAS and SATA.^[6]

• Systems identify SATA devices by their port number connected to the host bus adapter or by their universally unique identifier (UUID), while SAS devices are uniquely identified by their World Wide Name (WWN).
• SAS protocol provides for multiple initiators in a SAS domain, while SATA has no analogous provision.^[6]
• Most SAS drives provide tagged command queuing, while most newer SATA drives provide native command queuing.^[6]
• SATA uses a command set that is based on the parallel ATA command set and then extended beyond that set to include features like native command queuing, hot-plugging, and TRIM. SAS uses the SCSI command set, which includes a wider range of features like error recovery, reservations and block reclamation. Basic ATA has commands only for direct-access storage. However SCSI commands may be tunneled through ATAPI^[6] for devices such as CD/DVD drives.
• SAS hardware allows multipath I/O to devices while SATA (prior to SATA 2.0) does not.^[6] Per specification, SATA 2.0 makes use of port multipliers to achieve port expansion, and some port multiplier manufacturers have implemented multipath I/O using port multiplier hardware.
• SATA is marketed as a general-purpose successor to parallel ATA and has become common in the consumer market, whereas the more-expensive SAS targets critical server applications.
• SAS error-recovery and error-reporting uses SCSI commands, which have more functionality than the ATA SMART commands used by SATA drives.^[6]
• SAS uses higher signaling voltages (800–1,600 mV for transmit, and 275–1,600 mV for receive^{[clarification needed]}) than SATA (400–600 mV for transmit, and 325–600 mV for receive^{[clarification needed]}). The higher voltage offers (among other features) the ability to use SAS in server backplanes.^[6]
• Because of its higher signaling voltages, SAS can use cables up to 10 m (33 ft) long, whereas SATA has a cable-length limit of 1 m (3.3 ft) or 2 m (6.6 ft) for eSATA.^[6]
• SAS is full duplex, whereas SATA is half duplex. The SAS transport layer can transmit data at the full speed of the link in both directions at once, so a SCSI command executing over the link can transfer data to and from the device simultaneously. However, because SCSI commands that can do that are rare, and a SAS link must be dedicated to an individual command at a time, this is generally not an advantage.^[7]

 

 

TL;DR: SAS drives are for enterprise environments where more demanding hardware and protocols are required.

And i meant SCSI.

[Sunshine1868]

And i meant SCSI.

 

like real SCSI?? please show pics of this server, you've peaked my interest.

[TubsAlwaysWins]

like real SCSI?? please show pics of this server, you've peaked my interest.

Its not this server. Its THESE servers

[TubsAlwaysWins]

like real SCSI?? please show pics of this server, you've peaked my interest.

[Sunshine1868]

What do you plan on doing with this?

it may actually be cheaper to find a more modern (and far more powerful) server on eBay for the price of a few drives for this old machine

[TubsAlwaysWins]

What do you plan on doing with this?

it may actually be cheaper to find a more modern (and far more powerful) server on eBay for the price of a few drives for this old machine

No idea. I would do a NAS but they dont have the drive space. Maybe a minecraft server or just a fun linux machine

[Sunshine1868]

No idea. I would do a NAS but they dont have the drive space. Maybe a minecraft server or just a fun linux machine

 

I hope you didn't pay a lot for this machine... Like I said, you can pick up a nice, new(ish) server off eBay for a couple hundred bucks

[TubsAlwaysWins]

I hope you didn't pay a lot for this machine... Like I said, you can pick up a nice, new(ish) server off eBay for a couple hundred bucks

It was free. They were just sitting on a shelf where i work, and i was told i could have them

 

Edit: and i don't have a couple hundred bucks for one. all my money goes to my main computer right now

[TubsAlwaysWins]

I hope you didn't pay a lot for this machine... Like I said, you can pick up a nice, new(ish) server off eBay for a couple hundred bucks

All i know is there are 2 3.2Ghz Xeons in one so im happy

[Sunshine1868]

All i know is there are 2 3.2Ghz Xeons in one so im happy

 

instructions/cycle is more important than clock speed  

[TubsAlwaysWins]

instructions/cycle is more important than clock speed

yep. I have no idea what to do with it. In order to put linux on it i need a custom bootloader that starts from a floppy drive

[Sunshine1868]

Garbage day.