[SOLVED] SSD

sycamorex · 07-20-2011, 06:35 PM

Apart from the user (ie. myself), the weakest link in my box are definitely my hard drives (2 IDEs, 1 SATA). Despite the fact that I've got plenty of RAM for my needs and a good processor, sometimes I'm not entirely satisfied with the speed of things. Sometimes when I startx to KDE, I can literally hear the HD sweating. Apart from my regular backups of most important stuff, I've started the process of backing up everything. I want to replace those 2 IDE drives with something quicker.
I am wondering if the ssd drives are worth the money. I thought perhaps I could buy 1 ssd drive for the operating system, and one SATA for data.

What are your experiences with ssd drives on linux?

thanks

TobiSGD · 07-20-2011, 06:57 PM

I replaced the disk in my laptop with an Intel X25-V SSD (40GB) which is a value edition. This gives me very good read-speed, but not so good write-speed. Not so important on a desktop machine, but it gave me almost an hour more battery live. Also program start up times are recognizable faster. Of course only the first time when I start an app, the second time on a machine with enough RAM the app should start from cache. Here just a small example:

Code:

root@dragon ~ :) # hdparm -tT /dev/sda

/dev/sda:
 Timing cached reads:   1774 MB in  2.00 seconds = 887.42 MB/sec
 Timing buffered disk reads: 746 MB in  3.01 seconds = 248.08 MB/sec

While it is (logically) a no-go to have a separate data-drive in my laptop, I am thinking about replacing the OS-disk in my desktop with a small SSD. The /home-partition is already on a RAID-0 array (which is of course backed up to a different disk regularly). This way I would treat the SSD with care, have enough space for additional programs and use the mechanical drives for data that changes often. According to my experiences with the laptop this should give a good speed-up.

sycamorex · 07-20-2011, 07:16 PM

Thanks for your input.
If SSD drives shouldn't be exposed to a huge number of 'writes', then ideally /temp, /var/log should be mounted on some other drive, shouldn't it? By doing this, we, however, spread the system on two separate physical drives, which IMO would decrease performance/speed. Is that correct?

onebuck · 07-20-2011, 08:01 PM

Hi,

Not a problem for newer SSD.
I like the Intel X25 drives. Placed one in my Dell laptop. Quick & clean operation. Very pleased with cost & usability for newer Intel SSD.

Next one will be a Corsair SSD to experiment with their controller. Lot more $$.

TobiSGD · 07-20-2011, 08:33 PM

Quote:

Originally Posted by sycamorex

Thanks for your input.
If SSD drives shouldn't be exposed to number of 'writes', then ideally /temp, /var/log should be mounted on some other drive, shouldn't it?

Yes. Since this isn't really possible on my laptop I mount /tmp and /home/tobi/.cache (I am the only user of this machine) to RAM with tmpfs.

Quote:

By doing this, we, however, spread the system on two separate physical drives, which IMO would decrease performance/speed. Is that correct?

No, actually this should increase the performance in some times, normally you shouldn't see a difference, but I can't see any case where it should decrease performance. Since you are a Slacker, just one example. If you install a package via sbopkg or a Slackbuild the actual compiling (the working on the data) will take place on one drive (where /tmp is mounted if you use standard settings), while the needed programs (make, gcc, ...) are loaded from the SSD. This way the loading of a necessary program, reading of library headers and so on will not disturb the drive that actually does the work with head-movements and taking up bandwith.

sycamorex · 07-21-2011, 06:52 AM

Thanks for your replies.
Onebuck:

Quote:

Not a problem for newer SSD.

I've been reading about it and it does seem that the issue of a limited number of write cycles has been exagerrated.

Quote:

Next one will be a Corsair SSD to experiment with their controller. Lot more $$.

Is there any particular one you have in mind? Is there anything special about their controller?

Tobi:

Quote:

Yes. Since this isn't really possible on my laptop I mount /tmp and /home/tobi/.cache (I am the only user of this machine) to RAM with tmpfs.

That's smart. I like this workaround.

Quote:

No, actually this should increase the performance in some times, normally you shouldn't see a difference, but I can't see any case where it should decrease performance. Since you are a Slacker, just one example. If you install a package via sbopkg or a Slackbuild the actual compiling (the working on the data) will take place on one drive (where /tmp is mounted if you use standard settings), while the needed programs (make, gcc, ...) are loaded from the SSD. This way the loading of a necessary program, reading of library headers and so on will not disturb the drive that actually does the work with head-movements and taking up bandwith

Ok, I see your point.

I've never had any ssd drive in my hand so I'll ask a few dumb questions:
1. what cable is used to connect a ssd drive to the MB (is it just a normal SATA cable)?
2. If they are 2.5", do you need any kind of frames to fit them in a computer chassis?

thanks guys.

TobiSGD · 07-21-2011, 07:36 AM

1. Yes, it is a normal SATA-connector.
2. Yes, they came in a bundle with my Intel SSD, don't know about other brands, but if you have to buy them, they are pretty cheap. EDIT: It also depends on the case, some newer cases already have one or two 2,5"-bays.

onebuck · 07-21-2011, 09:21 AM

Hi,

The following links should help you to understand things;

SandForce 1222 SSD Testing, Part 1: Initial Throughput Results
SandForce 1222 SSD Testing - Part 2: Initial IOPS Results
SandForce 1222 SSD Testing, Part 3: Detailed Throughput Analysis
SandForce 1222 SSD Testing, Part 4: Detailed IOPS Analysis

Corsair Force-Series specs generally;

Quote:

Based on the latest Sandforce SF-1200 SSD Processor, the Corsair Force Series Solid-State Drive offers stutter-free response, fast performance, cooler and quieter operations for your notebook, netbook, and desktop PC.

F60 SSD page has more than enough information;

Quote:

tech specs;
Warranty Three years
Dimension No
SSD Unformatted Capacity 60 GB
Max Sequential Read/Write (using ATTO Disk Benchmark) 285 MB/s sequential read — 275 MB/s sequential write
Max Random 4k Write (using IOMeter 08) 50k IOPS (4k aligned)
Interface SATA 3Gb/s
Technology High-reliability MLC NAND flash
Form Factor 2.5 inch
DRAM Cache Memory No
Weight 80g
Voltage 5V ±5%
Power Consumption (active) 2.0W Max
Power Consumption (idle/standby/sleep) 0.5W Max
S.M.A.R.T. Support Yes
Shock 1500 G
MTBF 1,000,000 hours

Please note the underlined above concerning 4K aligned provides 50k IOPS (IOPS – IO Operations Per Second) for random 4K writes.

Capacities for the Corsair are available up to 240GB for the F-series. Not cheap either! MSRP for 'Corsair Force Series GT SSD 2.5" 60GB CSSD-F60GBGT-BK' $169.99 U.S.

But this same drive can be found for $144.99 at NewEgg. I think Tigerdirect had the same drive price but you paid shipping.

I'll need to update my prices before a purchase of the Force Series™ F240A Solid-State Hard Drive.

I'm not worried about the number of writes for the newer SSD since a upgrade will most likely be done before the wear level is ever reached for laptop operations.

You might consider a Hybrid drive if writes are a concern: Seagate 320GB SATA 2.5" SSD Hybrid Drive for $85 + free shipping.

A hybrid adapter would be another interface methodology to marry SATA SSD & SATA HDD.

HTH!

sycamorex · 07-21-2011, 09:44 AM

Thanks guys.

I'll read the links posted by onebuck and come back with futher questions (I'm sure I'll have some).

onebuck · 07-21-2011, 09:54 AM

Hi,

Your Welcome!

sycamorex · 07-21-2011, 05:27 PM

I found this drive with SF-2200 controller. It's only 60GB but I don't need anything more for the system.
http://www.ebuyer.com/product/272788
What do you think?

Although the number of writes might not be such an issue any longer, I like Tobi's idea of mounting /tmp in RAM with tmpfs (it deals with clearing it at the same time)

Are there any special kernel parameters that should be used with ssd drives? What about a filesystem (and mount parameters)? I've read mixed opinions about whether journaling will decrease the lifespan or not. Mind you, most of the articles I read were from ca. 2009 so they might not apply to newer drives.

Thanks guys.

TobiSGD · 07-21-2011, 05:39 PM

I use ext4 on that drive, with journaling, just make sure to have the mount-option discard for the partitions on the SSD in your fstab to activate the TRIM feature. I also don't have an customizations especially for the SSD in the kernel, but if there is one I would benefit from I also would like to know.

EDIT: Wow, that really is a fast drive, but keep in mind that you need a SATA 3.0 (sometimes called SATA 6G) connector on your mainboard for its full performance.

sycamorex · 07-21-2011, 07:25 PM

Quote:

Originally Posted by TobiSGD

I use ext4 on that drive, with journaling, just make sure to have the mount-option discard for the partitions on the SSD in your fstab to activate the TRIM feature. I also don't have an customizations especially for the SSD in the kernel, but if there is one I would benefit from I also would like to know.

EDIT: Wow, that really is a fast drive, but keep in mind that you need a SATA 3.0 (sometimes called SATA 6G) connector on your mainboard for its full performance.

Thanks. My MOBO fully supports it, but I'm just wondering how reliable the specifications are. It's probably the maximum possible speed that will be unlikely to be achieved in real life.

cascade9 · 07-22-2011, 09:51 AM

Quote:

Originally Posted by sycamorex

Thanks. My MOBO fully supports it, but I'm just wondering how reliable the specifications are. It's probably the maximum possible speed that will be unlikely to be achieved in real life.

The SATA (and IDE, SCSI etc) standard are 'up to' speed XXXXX, not 'always will be'.

That is why TobiSGD said you would need SATAIII to use that drive at 'full performance'. Its faster than SATAII, but nowhere near to limit of SATAIII.

Given a few more years of SSD development, maybe we will start seeing SSD that saturate SATAIII bandwidth. Right now, that is not happening.

sycamorex · 07-22-2011, 10:05 AM

Quote:

Originally Posted by cascade9

The SATA (and IDE, SCSI etc) standard are 'up to' speed XXXXX, not 'always will be'.

That is why TobiSGD said you would need SATAIII to use that drive at 'full performance'. Its faster than SATAII, but nowhere near to limit of SATAIII.

Given a few more years of SSD development, maybe we will start seeing SSD that saturate SATAIII bandwidth. Right now, that is not happening.

I've just bought that drive and a SATA III cable, which apparently is exactly the same as a SATA II cable. It's all marketing, but I didn't have a spare one anyway.

Next week, I'll set it up and will be able to post some benchmarks.