Mac OS X SSD tweaks

http://blogs.nullvision.com/?p=275

by bensummers • 16 years ago

62 37 16 years ago

blogs.nullvision.com

wmf2• 16 years ago

IMO these go beyond tweaks and are more like SSD ricing.

Nwallins• 16 years ago

noatime is a great counterexample to your 'ricing' claim. I run this mount option on nearly every filesystem under my command. relatime is also a viable option if you need things like mutt.

From http://kerneltrap.org/node/14148 (which discusses relatime, a less-drastic version of noatime that keeps mutt working)

> Ingo Molnar stressed the significance of fixing this performance issue, "I cannot over-emphasize how much of a deal it is in practice. Atime updates are by far the biggest IO performance deficiency that Linux has today. Getting rid of atime updates would give us more everyday Linux performance than all the pagecache speedups of the past 10 years, _combined_."

> "It's also perhaps the most stupid Unix design idea of all times. Unix is really nice and well done, but think about this a bit: 'For every file that is read from the disk, lets do a ... write to the disk! And, for every file that is already cached and which we read from the cache ... do a write to the disk!'"

mbreese2• 16 years ago

What's the issue really? There are three things mentioned, none of which is very controversial (okay, so part of the last one is).

* noatime - which is a standard setting on Linux these days

* Remove the hibernate file - which is valid, if you know the tradeoffs. And the author does describe them sufficiently.

* Move temporary files to ramdisks - this is a pretty common speedup too. The controversial part is what to put in the ramdisk.

DenisM2• 16 years ago

Sadly, no performance data is provided.

Luyt2• 16 years ago

But these are not tweaks to optimize performance - they're for reducing the number of writes to the SSD somewhat. Now that I think of it, one could indeed view those writes as a performance metric (better being: less writes).

DenisM2• 16 years ago

Is it really better, or is it just a fell-good thing? What if reducing number of writes has no practical consequences at all? There is no data provided to judge either way.

barredo• 16 years ago

Here's a link to a more recent post in other blog http://damieng.com/blog/2010/04/09/macbook-pro-upgrade-to-cr... — Author switched original 320GB MacbookPro HDD with a Crucial 256GB SSD, it provides benchmarks and compared perfomance and an interesting points:

Don’t go with Apple’s factory-options for an SSD as they use slower Samsung drives and charge a premium for it which is unacceptable especially given how easy they are to replace.

Which I hope, if true, Apple will fix by adding high-end SSD options in the near future

blasdel3• 16 years ago

Intel only sells their awesome SSDs retail, as demand far outstrips their inconsistent supply. When they get their production up and start offering them to OEMs, expect Apple to start using them.

I don't see Apple using any of the mediocre inconsistently-performing Taiwanese SSDs.

PStamatiou2• 16 years ago

For what it's worth, here's a link to my review/how to of an X25-M G2 RAID 0 array on my MacBook Pro with some basic benchmarks: http://paulstamatiou.com/how-to-apple-macbook-pro-raid-0-arr...

uuid5• 16 years ago

Another way to save (the oh so precious) space on SSDs is to apply HFS+ compression to files.You can use ditto(1) or this GUI: http://latenitesoft.com/squeeze/

Note, however, that files are decompressed on writes, so don't try it on anything large and frequently written to.

sumeeta• 16 years ago

Is there really a serious issue in the way OS X handles SSDs?

I think I want to replace my MacBook’s hard disk with an SSD, but I’m afraid of having to spend hours rigging out the best configuration. Do you have to play with settings if you order a Mac from Apple with an SSD pre-installed?

It seems like if I want to just plug an SSD in and get on with my life, I’ll have to wait for an OS X update. Unless this is all just PC-ricer talk that’s safe to ignore…

uuid5• 16 years ago

As long as you leave plenty of free space, SSDs work great out of the box. Don't ever fill them (something beyond 80% capacity), or you will crush performance. The tweaks in the article are attempts to optimize for the last 2%, but in no way necessary.

rufo4• 16 years ago

Since you're going to be reading and writing to the drive repeatedly, the drive is always going to hit the write performance crunch no matter what you do (unless you support TRIM - Windows 7 does with the correct drivers, OS X does not, not sure about Linux).

However, even degraded, write performance of a modern SSD will still make a hard drive look like yesterday's news - so honestly, I wouldn't even worry about it at all.

Luyt2• 16 years ago

You can indeed get a SSD in a Mac Air as an option. Does Apple treat those different in OSX? I'm not sure.

I replaced the mechanical harddisk in my MacMini with a SSD about a year ago. It broke down last week. I don't think OSX is to blame, since I put the same model SSD in my Windows and FreeBSD machines at the same time (the FreeBSD box is always on and pretty busy), and no problems there yet. Except for the 'noatime' I didn't take any special precautions.

catch232• 16 years ago

Most of the tweaks in the blog article have little to do with SSD. I seriously doubt any of the tweaks in the article will have any longer term effects on the actual usage of the SSD.

mbreese2• 16 years ago

They are all pretty much designed to minimize the amount of writes to the SSD. This is more about extending the longevity of the SSD than anything else.

wrs• 16 years ago

I installed an SSD in my MBP some months ago, and it is fantastic. Just do it. Don't worry about hacking the settings--the OS folks at Apple will eke out the last few percent of perf for us when they get around to it.

rufo4• 16 years ago

Given that Intel SSDs are claimed to support writing 100GB of data every day for five years before losing the ability to write, and I rarely hit even 10GB written in a bus development day according to OS X's Activity Monitor, I'm uncertain if these tweaks will make all that much of a difference in the lifespan of the drive.

mrkurt• 16 years ago

It's not so much the lifespan, it's performance degradation after lots of the drive has been written to. It's not a permanent problem, but I know lots of people who notice and end up formatting to regain their performance.

cdr2• 16 years ago

As far as I'm aware, TRIM takes care of the performance degradation. Not sure that OSX supports TRIM yet though.

PStamatiou2• 16 years ago

For what it's worth my first Intel SSD (X25-M G1) died in under a year and I wasn't pushing anywhere near that much data.

jawn• 16 years ago

For those like me who came away from this wondering what windows tweaks were available, I found a good thread here: http://www.ocztechnologyforum.com/forum/showthread.php?47212...

It is a lot of the same types (ramdrives, no hibernation) of changes but for windows users.

Mac OS X SSD tweaks

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