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Weird SSD issue/question

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FudgeNuggets

Member
Joined
Mar 2, 2006
Location
Gone Racing
I've got a Vertex 64GB SSD drive with a 54GB and a 10GB partition. I've got a 3Gb/s SATA controller. If I save an 8GB file to one partition and then copy it to another, why is it taking about 8 minutes to copy? Shouldn't it be like damn near supersonic in speed?
 

johan851

Insatiably Malcontent, Senior Member
Joined
Jul 24, 2002
Location
Seattle, WA
If your write speed is 50mb/s, and your read speed is 150mb/s, for 8GB I get:

Write: 165 seconds
Read: 55 seconds

That's almost four minutes of your time. It's possible that it's not reading/writing at optimal speed because of degradation over time. There's also some overhead associated with reading/writing simultaneously, I'm sure.

8 minutes is a while, but it's not ridiculous.
 
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FudgeNuggets

Member
Joined
Mar 2, 2006
Location
Gone Racing
If your write speed is 50mb/s, and your read speed is 150mb/s, for 8GB I get:

Write: 165 seconds
Read: 55 seconds

That's almost four minutes of your time. It's possible that it's not reading/writing at optimal speed because of degradation over time. There's also some overhead associated with reading/writing simultaneously, I'm sure.

8 minutes is a while, but it's not ridiculous.

I was thinking that with a journalled HDD though that it was just moving the file ids on the drive and not actually physically moving the file. I mean I could understand if I was copying from an external or another drive but from one SSD partition to another partition on the same SSD drive, I was thinking it would just take a few seconds to rewrite the location in the file allocation table? Am I wrong here? If I am, here are the speed benches on the HDD. I'm still thinking that 8 minutes is a long time. According to the bench speed say go on the low end of 100MB a sec it should take 10 sec to write one GB or 80 sec to write 8GB which is 1.5 minutes not 8.

Disk Test 211.57
Sequential 189.13
Uncached Write 215.80 132.50 MB/sec [4K blocks]
Uncached Write 212.55 120.26 MB/sec [256K blocks]
Uncached Read 128.04 37.47 MB/sec [4K blocks]
Uncached Read 250.00 125.65 MB/sec [256K blocks]
Random 240.06
Uncached Write 83.12 8.80 MB/sec [4K blocks]
Uncached Write 379.39 121.46 MB/sec [256K blocks]
Uncached Read 2558.97 18.13 MB/sec [4K blocks]
Uncached Read 622.81 115.57 MB/sec [256K blocks]
 

Evilsizer

Senior Forum Spammer
Joined
Jun 6, 2002
ok well i just did a test.. i dont have a second partion on my raid'd drives. i did do a copy of 10.2gig's two games, bioshock and stalker clear sky both patched. watched the clock in win7, took 1min 30sec to copy them to another folder. according to windows i had a sustained write speed of 115mb/s. it did move up to a high of 125mb/s for about 5-10secs, lowest was 110mb/s for the same amount of time.

my question is, are both using the same file system? if no, are the file systems aligned for ssd's? i dont know all the file systems for HD's or which ones from linux have or dont have alignment problems.
 
Last edited:

johan851

Insatiably Malcontent, Senior Member
Joined
Jul 24, 2002
Location
Seattle, WA
I was thinking that with a journalled HDD though that it was just moving the file ids on the drive and not actually physically moving the file. I mean I could understand if I was copying from an external or another drive but from one SSD partition to another partition on the same SSD drive, I was thinking it would just take a few seconds to rewrite the location in the file allocation table?
If you did a move operation that might be the case. Not sure how it would work across two partitions - my guess is that it might actually move the data from one set of cells to another, especially if (like evilsizer said) the file systems were different.

You did a COPY, though, and to copy something you need to actually read the entire file and then write it to another location. If it just changed the file ids you wouldn't end up with two copies - you would still only have one.
 
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FudgeNuggets

Member
Joined
Mar 2, 2006
Location
Gone Racing
ok well i just did a test.. i dont have a second partion on my raid'd drives. i did do a copy of 10.2gig's two games, bioshock and stalker clear sky both patched. watched the clock in win7, took 1min 30sec to copy them to another folder. according to windows i had a sustained write speed of 115mb/s. it did move up to a high of 125mb/s for about 5-10secs, lowest was 110mb/s for the same amount of time.

my question is, are both using the same file system? if no, are the file systems aligned for ssd's? i dont know all the file systems for HD's or which ones from linux have or dont have alignment problems.

That's what I thought I'd get but I'm only getting like 10-30mb/s. This is troubling....... I'm going to reboot and try again. Oh and both partitions are HFS+ Journaled.
 
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FudgeNuggets

Member
Joined
Mar 2, 2006
Location
Gone Racing
Just tested it in Windows 7 and it is blazing fast. It looks like it is something with Snow Leopard. I'm getting so sick of SL that I'm on the edge of just using Win7 or switching to Mint Linux.
 

SuperDave1685

Member
Joined
Jul 22, 2002
Location
USMC.. OoRah!!
Just to throw this out there - SSDs really shine in small, random writes and reads. It has to deal with the way the NAND Flash memory reads and write to individual pages and blocks. SSD's are great for OS's and applications.

1) SSDs are not the best storage medium when it comes to transferring large files (such as 8Gb). Standard mechanical HD's still hold a large lead in this one task. It has to do with the fact that a SSD cannot write and erase individual pages at a time. I tmust do entire blocks, saving the block's contents to its cache, erasing the block, and re-writing it. That takes time. So you shouldn't be surprised that it taking so long to transfer such a large file.

2) With a little less than 50% left on the hard drive, you could be experiencing some degradation. I'd suggest you secure erase the drive, try upgrading it's firmware and have another go at it. Of course back up all your data. If you want, you could just make a drive image to help save you some time.
 
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FudgeNuggets

Member
Joined
Mar 2, 2006
Location
Gone Racing
Just to throw this out there - SSDs really shine in small, random writes and reads. It has to deal with the way the NAND Flash memory reads and write to individual pages and blocks. SSD's are great for OS's and applications.

1) SSDs are not the best storage medium when it comes to transferring large files (such as 8Gb). Standard mechanical HD's still hold a large lead in this one task. It has to do with the fact that a SSD cannot write and erase individual pages at a time. I tmust do entire blocks, saving the block's contents to its cache, erasing the block, and re-writing it. That takes time. So you shouldn't be surprised that it taking so long to transfer such a large file.

2) With a little less than 50% left on the hard drive, you could be experiencing some degradation. I'd suggest you secure erase the drive, try upgrading it's firmware and have another go at it. Of course back up all your data. If you want, you could just make a drive image to help save you some time.

I'm going to give it a shot. Just made a time machine back up.
 

HDCHOPPER

Member
Joined
Mar 6, 2008
Does Linux /Snow lepoard automatic align like Vista & W7 ? ..

I know you Must align XP but Vista & W7 do it by default but I know Nothing about all the Linux os's OSX ect...

Could be it if it doesn't align by default ;)

To test just align the drive first partition at 1024k and any partition after that will be aligned too and put SL back on andcheck it out ...