Raid 0 SSD and HDD

[Goliath002]

I have a question what will happen if I Raid 0 an SSD and a HDD, I have a HDD that im not using, what are the cons and the pros about it?

im just looking performance for my OS not for storage, will it be better? will it be reliable?

 

current speeds:

HDD: 51MB/s Read, 50 MB/s Write

SSD: 438.2MB/s Read, 465MB/s Write

[paulsterio]

Why would you RAID0 an SSD and a HDD? 

 

You can possibly use the SSD as a cache, but that looks like a pretty old and slow HDD. 

[roberto++]

 I highly do not recommend doing this, leave the HDD and SSD separate. this will likely be a very unreliable setup.

I have a question what will happen if I Raid 0 an SSD and a HDD, I have a HDD that im not using, what are the cons and the pros about it?

im just looking performance for my OS not for storage, will it be better? will it be reliable?

 

current speeds:

HDD: 51MB/s Read, 50 MB/s Write

SSD: 438.2MB/s Read, 465MB/s Write

[Sheldon_King]

I have a question what will happen if I Raid 0 an SSD and a HDD, I have a HDD that im not using, what are the cons and the pros about it?

im just looking performance for my OS not for storage, will it be better? will it be reliable?

 

current speeds:

HDD: 51MB/s Read, 50 MB/s Write

SSD: 438.2MB/s Read, 465MB/s Write

Your performance will actually be worse running them in RAID 0 than it would be to just run them as separate drives, or using the SSD as a cache drive.

The reason specifically not to do this is because the SSD will be bottlenecked by the HDD in the RAID array. Just assuming write speeds of 400 and 50, the RAID array would have a write speed of about 100MB/s. You will also be hitting the SSD with more writes, and thus cause it to fail sooner. Running them separately, you will get teh fastest performance from both, as well as reducing points of failure.

 

Different subject entirely, but how old is that HDD? With those speeds, you could likely get better performance by getting a newer drive (most modern 7200RPM drives run ~125-150 MB/s, triple as fast as yours, more or less).

[Antistatic12]

In general terms:
Will it be better? Performance of RAID 0 is better than a standard SSD/HDD performance. (Discounting PCI SSD's.)
Will it be reliable? RAID 0 is easy to setup and provided you use quality parts is reliable for everyday use in a person's PC for the most part. In terms of the drives, if one fails then it is bye bye to whatever data on them. That being the major drawback.

Would I recommend RAID 0 for what you propose, no. Would I recommend RAID 0 on SSD's at all. Probably not, (maybe for benching)

For RAID 0/1 it is a unwritten law to use the same drives. just easier and less headaches.

Small SSD for OS, large HDD for everything else. Or if you can just use SSD's like me.

Isn't RAID like networking, it is only fast as the slowest component. That being the drives, so if you had a HDD and SSD, you would be doing your self a major diservice

[brob]

I have a question what will happen if I Raid 0 an SSD and a HDD, I have a HDD that im not using, what are the cons and the pros about it?

im just looking performance for my OS not for storage, will it be better? will it be reliable?

 

current speeds:

HDD: 51MB/s Read, 50 MB/s Write

SSD: 438.2MB/s Read, 465MB/s Write

 

RAID 0 arrays operate at the speed of the slowest drive. Drive capacity is based on the size of the smallest drive. So you would end up with an array twice the capacity of your SSD running at your HDD speeds.

[Sheldon_King]

RAID 0 arrays operate at the speed of the slowest drive. Drive capacity is based on the size of the smallest drive. So you would end up with an array twice the capacity of your SSD running at your HDD speeds.

That is not right. RAID 0 doubles teh speed of teh slowest drive and uses double the capacity of the smallest drive.

[brob]

That is not right. RAID 0 doubles teh speed of teh slowest drive and uses double the capacity of the smallest drive.

 

I said the capacity was "based on the size of the smallest drive". If one has four drives in a RAID 0, the size of the array is 4 x the capacity of the smallest drive.

[Sheldon_King]

I said the capacity was "based on the size of the smallest drive". If one has four drives in a RAID 0, the size of the array is 4 x the capacity of the smallest drive.

I know what you said. You also said it operates at the speed of the slowest drive which is a lie.

Speed is (# of drives)x(the read or write rate of the slowest drive). Capacity is not exactly going to line up, but it is more or less (number of drives)x(capacity of smallest drive). 

 

THe way you said it originally, 2 250MB/s drive in RAID 0 operate at 250MB/S, when it is closer to 500MB/s (In reality it would be around 475MB/s), Assuming 2 250GB drives, then you get more or less 500GB (It is going to be closer to 490GB in most cases).

[brob]

I know what you said. You also said it operates at the speed of the slowest drive which is a lie.

Speed is (# of drives)x(the read or write rate of the slowest drive). Capacity is not exactly going to line up, but it is more or less (number of drives)x(capacity of smallest drive). 

 

THe way you said it originally, 2 250MB/s drive in RAID 0 operate at 250MB/S, when it is closer to 500MB/s (In reality it would be around 475MB/s), Assuming 2 250GB drives, then you get more or less 500GB (It is going to be closer to 490GB in most cases).

 

I said the array operates at the speed of the slowest drive. It may be incorrect, I don't think so, but it is not a "lie". Writes involving the slowest drive are the speed at which the array is operating. A write completion cannot occur until that write has finished.

[Sheldon_King]

I said the array operates at the speed of the slowest drive. It may be incorrect, I don't think so, but it is not a "lie". Writes involving the slowest drive are the speed at which the array is operating. A write completion cannot occur until that write has finished.

The way you are attempting to explain it is a lie. The array is faster than the slowest drive in RAID0. Where N is the number of drives and x is the speed of the slowest drive, the write (and read) rate of a RAID 0 array is xn up to a point. 6 100MB/s drives will run at 600MB/s, and 1 500MB/s drive with 3 100MB/s drives will run at 400MB/s. The slowest drive is the variable, not a constant, which is what you are trying to say.

 

**UP to a point means that there is a point where the increasing speed no longer adhears to the xn rate. If you have an array with 60 100MB/s drives, you are not going to get close to 6000MB/s in most cases (But a lot of that depends on the drives and the RAID controller). And in no way am I saying it is a good idea to RAID 0 60 drives. That is an insanely stupid idea (RAID 50/60/5/6 would be far better for such a large array).

[Goliath002]

ok.......................

 

 

If I have the time and im not lazy Ill do it just to test the performance,  im just curious I want to see what it will do

[brob]

The way you are attempting to explain it is a lie. The array is faster than the slowest drive in RAID0. Where N is the number of drives and x is the speed of the slowest drive, the write (and read) rate of a RAID 0 array is xn up to a point. 6 100MB/s drives will run at 600MB/s, and 1 500MB/s drive with 3 100MB/s drives will run at 400MB/s. The slowest drive is the variable, not a constant, which is what you are trying to say.

 

**UP to a point means that there is a point where the increasing speed no longer adhears to the xn rate. If you have an array with 60 100MB/s drives, you are not going to get close to 6000MB/s in most cases (But a lot of that depends on the drives and the RAID controller). And in no way am I saying it is a good idea to RAID 0 60 drives. That is an insanely stupid idea (RAID 50/60/5/6 would be far better for such a large array).

 

You need to look up the definition of the word "lie". I am not a liar and deeply resent the accusation.

[Sheldon_King]

You need to look up the definition of the word "lie". I am not a liar and deeply resent the accusation.

the meaning of the word (by websters dictionary) is "to create a false or misleading impression ", which is exactly what you did. You said "the array operates at the speed of the slowest drive" which is not in teh least right for RAID 0. It would be right for RAID 1, but not 0. It is x times the slowest drive, which is not operating at the speed of the slowest drive. Operating at the speed of the slowest drive means that if the slowest drive runs at 200MB/s, then teh entire RAID 0 array has a maximum speed of 200MB/s which is not in the least right.

 

If you want to be insulted or resent the word, you are welcome to do so. My intention is not to insult you. My intention is to bring out the truth despite your insertion of untrue "facts".

[brob]

the meaning of the word (by websters dictionary) is "to create a false or misleading impression ", which is exactly what you did. You said "the array operates at the speed of the slowest drive" which is not in teh least right for RAID 0. It would be right for RAID 1, but not 0. It is x times the slowest drive, which is not operating at the speed of the slowest drive. Operating at the speed of the slowest drive means that if the slowest drive runs at 200MB/s, then teh entire RAID 0 array has a maximum speed of 200MB/s which is not in the least right.

 

If you want to be insulted or resent the word, you are welcome to do so. My intention is not to insult you. My intention is to bring out the truth despite your insertion of untrue "facts".

 

Just who is being dishonest? From Websters 

Definition of LIE

intransitive verb

1

:  to make an untrue statement with intent to deceive

2

:  to create a false or misleading impression

transitive verb

:  to bring about by telling lies <lied his way out of trouble>

[Sheldon_King]

 

Just who is being dishonest? From Websters 

Definition of LIE

intransitive verb

1

:  to make an untrue statement with intent to deceive

2

:  to create a false or misleading impression

transitive verb

:  to bring about by telling lies <lied his way out of trouble>

 

And in just what way was the definition provided dishonest? Your copy + paste was the exact same definition which is "to provide a false or misleading impression". I never said you intended to deceive anyone, but rather that your understanding (or way of explaining, not sure which is at fault) is wrong. Either way, the statement you made that RAID 0 will only operate as fast as the slowest drive is a LIE. It is at the least misleading, and false at worst. It will operate at x times the slowest read and write rate, not at the rate of the slowest drive.