SSD - Is my OCZ Agility 3 sluggish?

fabertawe · 2011-11-03 18:04:05

Hi all,

I'll start off by saying it's actually very fast in desktop usage compared to my previous boot drive, a sata II MAXTOR STM3500320AS. Compared to the same drive tested on the wiki though, it seems to be running slow...

$ hdparm -Tt /dev/sdc
Me:
Timing cached reads:   8102 MB in  2.00 seconds = 4052.87 MB/sec
Timing buffered disk reads: 588 MB in  3.00 seconds = 195.98 MB/sec
Wiki:
Timing cached reads:   27738 MB in  2.00 seconds = 13889.38 MB/sec
Timing buffered disk reads: 1158 MB in  3.01 seconds = 385.08 MB/sec

$ dd if=/dev/zero of=tempfile bs=1M count=1024 conv=fdatasync,notrunc
Me:
1024+0 records in
1024+0 records out
1073741824 bytes (1.1 GB) copied, 2.29951 s, 467 MB/s
Wiki:
1073741824 bytes (1.1 GB) copied, 2.41537 s, 445 MB/s

$ echo 3 > /proc/sys/vm/drop_caches
$ dd if=tempfile of=/dev/null bs=1M count=1024
Me:
1024+0 records in
1024+0 records out
1073741824 bytes (1.1 GB) copied, 3.84744 s, 279 MB/s
Wiki:
1073741824 bytes (1.1 GB) copied, 2.35961 s, 455 MB/s

$ dd if=tempfile of=/dev/null bs=1M count=1024
Me:
1024+0 records in
1024+0 records out
1073741824 bytes (1.1 GB) copied, 0.283708 s, 3.8 GB/s
Wiki:
1073741824 bytes (1.1 GB) copied, 0.130664 s, 8.2 GB/s

Motherboard: ASUS M4A87TD EVO (sata 6Gb), Chipset: ATI RX780/RX790, Memory: 4096MB

$ parted -l
Model: ATA OCZ-AGILITY3 (scsi)
Disk /dev/sdc: 120GB
Sector size (logical/physical): 512B/512B
Partition Table: gpt

Number  Start   End     Size    File system  Name                 Flags
 1      1049kB  2097kB  1049kB               BIOS boot partition  bios_grub
 2      2097kB  120GB   120GB   ext4         Linux filesystem

As you can see I used gdisk for a GPT format, / and /home on partition 2 and burg installed to partition 1. I do have /var symlinked to the Maxtor drive though. Mounted ext4 in fstab with 'defaults,noatime,discard'.

I'm not sure if this is relevant...

$ hdparm -I /dev/sdc
	Model Number:       OCZ-AGILITY3                            
	Serial Number:      OCZ-V6CFIV5Q6C8ICJGC
	Firmware Revision:  2.15    
	Transport:          Serial, ATA8-AST, SATA 1.0a, SATA II Extensions, SATA Rev 2.5, SATA Rev 2.6, SATA Rev 3.0
Standards:
	Used: unknown (minor revision code 0x0110) 
	Supported: 8 7 6 5 
	Likely used: 8

but someone else with an Agility 3 had

	Supported: 9 8 7 6 5 
	Likely used: 9

Also, is this relevant?

$ smartctl -a /dev/sdc
ATA Version is:   8

which is the same as my sata II Maxtor drive.

I've tried using different sata ports (the MB has six) and also a different sata cable (also 6Gb). Any pointers or help greatly appreciated, thanks.

Last edited by fabertawe (2011-11-06 14:47:45)

.:B:. · 2011-11-04 08:05:43

I don't think your cables or S-ATA ports are the problem. If they were, you wouldn't hit 450+ MBps with dd. Your problem lies elsewhere.

Last edited by .:B:. (2011-11-04 08:06:09)

fabertawe · 2011-11-04 08:32:11

It's called "grasping at straws"

If anyone else with the same drive could do a 'hdparm -Tt /dev/sdX' that would be lovely. Also, could someone confirm my GPT alignment is actually correct?

Cheers

dl.zerocool · 2011-11-06 18:20:21

Hi @fabertawe

First if you don't have done it follow this wiki -> https://wiki.archlinux.org/index.php/Solid_State_Drives
For your tests write more than one Gig otherwise the tests are not going to be viable due to buffers etc.

Here is a set of tests I did a while ago :

*A little test and review of the OCZ AGILITY 3 120GO.*

I've run several tests on the SSD and excuted them at least five times, the ones that I put here are the ones
that represent the most the average speed of the SSD.

On some tests I added the max speed reach just as an indication,
I didn't do it for the min values because I was writing stuff, having firefox open and so on.
And as soon as my text editor tool auto saved my work the tests speed easily fell down by 50-100MB/s

The drive is connected to an EliteBook 8560w using SATA III.

## Simple read test
$ hdparm -t /dev/sda
/dev/sda:
Timing buffered disk reads: 1554 MB in 3.00 seconds = 517.47 MB/sec
---------------------------------------------------------------------

## Simple read test on disk and buffer test.
$ hdparm -Tt /dev/sda
/dev/sda:
Timing cached reads: 16070 MB in 2.00 seconds = 8046.52 MB/sec (Buffer speed)
Timing buffered disk reads: 1560 MB in 3.00 seconds = 519.52 MB/sec
---------------------------------------------------------------------

## Here I wrote a 8.6GB file to the SSD.
$ dd if=/dev/zero of=tempfile bs=2M count=4096
4096+0 records in
4096+0 records out
8589934592 bytes (8.6 GB) copied, 13.3059 s, 646 MB/s (Max was 720MB/s)
---------------------------------------------------------------------

## Here I read the file created just above.
$ dd if=tempfile of=/dev/null bs=2M count=4096
4096+0 records in
4096+0 records out
8589934592 bytes (8.6 GB) copied, 12.7617 s, 673 MB/s (Max was 698MB/s)
---------------------------------------------------------------------

## Here I clear the buffer-cache to accurately measure read speeds directly from the device
$ echo 3 > /proc/sys/vm/drop_caches
$ dd if=tempfile of=/dev/null bs=2M count=4096
4096+0 records in
4096+0 records out
8589934592 bytes (8.6 GB) copied, 17.5188 s, 490 MB/s (Max was 499MB/s clearing the cache each time)
---------------------------------------------------------------------

So OCZ seems to keep their promises, at least at more than 90%.

Here is the my fstab params I used to my ext 4 partitions (ext4 defaults,noatime,discard) (discard means TRIM feature)
*(Warning: It is critically important that users switch the controller driving the SSD to AHCI mode (not IDE mode) to ensure that the kernel is able to use the TRIM command.)*
*(Warning: Users need to be certain that kernel version 2.6.33 or above is being used AND that their SSD supports TRIM before attempting to mount a partition with the discard flag. Data loss can occur otherwise!)*
/ (ext4)
/home (ext4)
/boot (ext2)

And I also compile and use tmp directly in RAM because I've 8G available.
none /tmp tmpfs nodev,nosuid,noatime,size=3G,mode=1777 0 0
shm /dev/shm tmpfs nodev,nosuid,size=6G 0 0

And voilà !
You can find a lot of information in Archlinux wiki, just write in Google "Archlinux SSD".

I'm using noop scheduler

And I don't use GPT parts.

Last edited by dl.zerocool (2011-11-06 18:22:25)

fabertawe · 2011-11-07 09:26:27

Hi dl.zerocool, many thanks for taking the time to reply.

I did read the Wiki page and every other I could find. In fact, I've already read your "test and review" somewhere else too! I'd already incorporated your tests into a script I've been running and that's another reason why I think my drive's slow. Here is the output of that script comparing mine to yours...

$ ssd-speedtest sdb

/dev/sdb:
 Timing buffered disk reads: 578 MB in  3.00 seconds = 192.49 MB/sec
Ref: .. buffered disk reads: 1554 MB in 3.00 seconds = 517.47 MB/sec

/dev/sdb:
 Timing cached reads:   7950 MB in  2.00 seconds = 3976.75 MB/sec
 Timing buffered disk reads: 580 MB in  3.01 seconds = 192.79 MB/sec
Ref: .. cached reads:  16070 MB in 2.00 seconds = 8046.52 MB/sec (Buffer speed)
Ref: .. buffered disk reads: 1560 MB in 3.00 seconds = 519.52 MB/sec

4096+0 records in
4096+0 records out
8589934592 bytes (8.6 GB) copied, 17.238 s, 498 MB/s
Ref: ........... (8.6 GB) copied, 13.3059 s, 646 MB/s (Max was 720MB/s)

4096+0 records in
4096+0 records out
8589934592 bytes (8.6 GB) copied, 33.5123 s, 256 MB/s
Ref: ........... (8.6 GB) copied, 12.7617 s, 673 MB/s (Max was 698MB/s)

4096+0 records in
4096+0 records out
8589934592 bytes (8.6 GB) copied, 32.7515 s, 262 MB/s
Ref: ........... (8.6 GB) copied, 17.5188 s, 490 MB/s (max was 499MB/s)

As you can see there's a big discrepancy in the two sets of results. As I said I'm using ext4 with 'defaults,noatime,discard' and TRIM is definitely working. Thanks again for your interest.

Arch Linux

#1 2011-11-03 18:04:05

SSD - Is my OCZ Agility 3 sluggish?

#2 2011-11-04 08:05:43

Re: SSD - Is my OCZ Agility 3 sluggish?

#3 2011-11-04 08:32:11

Re: SSD - Is my OCZ Agility 3 sluggish?

#4 2011-11-06 18:20:21

Re: SSD - Is my OCZ Agility 3 sluggish?

#5 2011-11-07 09:26:27

Re: SSD - Is my OCZ Agility 3 sluggish?

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