do gentoo/compiling harm ssd's?

LoTeK · Apprentice Joined: 26 Jul 2012 Posts: 270

I've just read about why some people change from gentoo to arch (for those who understand german:
http://www.hardwareluxx.de/community/f211/gentoo-linux-oder-arch-linux-783591.html
that compiling alot harms ssd and that gentoo generally has to much writes to the harddrive... is this true?

anyway I don't understand why so many people complain about compile-time, one can do other things while compiling... for me the "compile everything yourself philosophy" was my main reason to change from mint/arch/fedora to gentoo... not even because it should run faster, but because it's cooler and "realer"

NeddySeagoon · Posted: Sat Nov 17, 2012 9:34 pm Post subject:

LoTeK,

In the early days of FLASH memories, write cycle life expectancy was about 1000 cycles. There was no wear leveling and the devices were too small and expensive to even think about using them is solid state drives.

Write life expectancy has improved, wear leveling exists, device capacity has increased and cost has plummeted.

There is anecdotal evidence on these forums that attempting to install Gentoo on the early 4G SSDs fitted to the eeepc would kill the drive before the install was complete.

Its no longer an issue.
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Computer users fall into two groups:-
those that do backups
those that have never had a hard drive fail.

LoTeK · Apprentice Joined: 26 Jul 2012 Posts: 270

NeddySeagon,

ok, good to hear that...

but is life expectancy still lower then the one of conventional harddrives? on my T420s I only have one 160GB SSD, but on my workstation I have a 128GB SSD and a 2TB HDD. Is it still a good idea to put /var and /tmp on the HDD for this reason? because now I have lvm2 with an extended volume group containing /home /var /tmp /opt and as far as I know I can't control if /var and /tmp are completely on the hdd

alkan · Posted: Sat Nov 17, 2012 10:11 pm Post subject:

if you have enough memory(RAM), you can put the 'var/tmp' on a tmpfs. That would reduce the writes to the SSD. Compile times are also faster as a side benefit.

NeddySeagoon · Posted: Sat Nov 17, 2012 10:12 pm Post subject:

LoTeK,

I have /tmp and /var/tmp/portage in RAM.
/tmp should only be small. If you need to put a DVD iso file somewhere before you burn it, /tmp is not the place. Somewhere in ./~ is better.
_________________
Regards,

NeddySeagoon

Computer users fall into two groups:-
those that do backups
those that have never had a hard drive fail.

logical_guy · Apprentice Joined: 18 Sep 2007 Posts: 268

can you post your fstab, neddy?

LoTeK · Apprentice Joined: 26 Jul 2012 Posts: 270

On the workstation I have 16G, so I can do it there, but I guess 4G is too small, although the 4 gigs are seldom working at full capacity I need sometimes everything...
my /tmp size is 10G.

Hypnos · Posted: Sat Nov 17, 2012 11:02 pm Post subject:

Memory is allocated to the tmpfs only as it's needed. So you'll only run into a problem if you're emerging something big and doing memory-intensive work at the same time.

I have /var/tmp/paludis on tmpfs (2560 Mib limit), and leave /tmp on the SSD since it gets few writes anyway compared to my home directory.
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cach0rr0 · Posted: Sat Nov 17, 2012 11:04 pm Post subject:

NeddySeagoon · Posted: Sat Nov 17, 2012 11:22 pm Post subject:

logical_guy,

Are you sure ?

LoTeK · Apprentice Joined: 26 Jul 2012 Posts: 270

lexming · Posted: Sun Nov 18, 2012 3:06 am Post subject:

My laptop is more than three years old and from day one it only has had one 128GB SSD drive in it. I use it everyday at work and home. No problems so far. So, IMO, the last of your problems on a desktop or laptop will be reaching the limit of writes of your drive. Most probably the machine will become obsolete before the SSD fails.

I do my compiling on RAM (but mainly because of the time gain). As cach0rr0 said, 4GB are not enough for everything. But in portage you can set different PORTAGE_TMPDIR for different packages. For example, I have the regular /var/tmp/portage in RAM to compile everything except Firefox and LibreOffice, which are compiled in /var/bigtmp that is located on the SSD.
This can be done through the /etc/portage/package.env. Here is my setup:

eccerr0r · Posted: Tue Nov 20, 2012 6:02 pm Post subject:

I also currently run Gentoo on SSDs, have three machines with SSD primary disks (32GB SSD/2GB RAM, 128GB SSD/4GB RAM and 180GB SSD/8GB RAM). I did not however do a full install from stage3, they were "stage4" type installs from a hard drive. I have the portage tree installed on the >100G disks.

However they all have gone through pretty much an "emerge -e world" because of the number of updates since first install.

I did find something interesting on my Crucial 128GB SSD - it records the average number of times the SSD cells have been erased. It currently is "3" (of 3000) and this includes the usage on the Windows partitions... It does not appear to be incrementing way too quickly despite the emerge updates, probably around 1 per month so far.

I tend to compile in tmpfs due to speed too, but when I run out of RAM I just let it go on the SSD. So far so good, and I even compile firefox (Libreoffice I use the binaries).

(I still have the 4GB SSD that came with my eeePC. It's too small to do anything really, I wonder how many write cycles it has left. The 4GB SSD was replaced with the 32GB SSD. I keep portage on an 8GB SD card, which I expect to fail much sooner than the 32GB...)
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cach0rr0 · Posted: Tue Nov 20, 2012 10:50 pm Post subject:

Hypnos · Posted: Tue Nov 20, 2012 11:11 pm Post subject:

cach0rr0 · Posted: Wed Nov 21, 2012 12:12 am Post subject:

mv · Watchman Joined: 20 Apr 2005 Posts: 6780

Hypnos · Posted: Wed Nov 21, 2012 1:02 am Post subject:

You need to do a cost/benefit analysis:

How much would it cost to compromise your data with and without TRIM enabled, and how do these compare to the value of your data?

How much is the speed of an SSD worth to you compared to the cost of using an SSD, with and without TRIM?
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Ion Silverbolt · Apprentice Joined: 04 Nov 2004 Posts: 203

I compile all my programs in a chroot from my desktop and install the binaries onto my netbooks SSD. The netbook has Gentoo on it yet never has compiled anything.

d2_racing · Posted: Wed Nov 21, 2012 4:41 am Post subject:

I have an Intel SSD 520 series and I use a big tmpfs 12 gigs for /var/tmp/portage and I use btrfs too.

cach0rr0 · Posted: Wed Nov 21, 2012 5:51 am Post subject:

Hypnos · Posted: Wed Nov 21, 2012 5:58 am Post subject:

So I guess the conclusion is that the security of your data is priceless to you.

For me, I just want to prevent identity theft. If I some NSA spook wants to read my diary entries, fine by me.

I may reevaluate if I ever become important.
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cach0rr0 · Posted: Wed Nov 21, 2012 6:10 am Post subject:

dmpogo · Advocate Joined: 02 Sep 2004 Posts: 3468 Location: Canada

ppurka · Advocate Joined: 26 Dec 2004 Posts: 3256

I compile stuff in tmpfs too (using 2G out of 4G RAM), except for firefox/chromium, oo/libreoo and thunderbird. I use the -bin versions of them. It's no use trying to compile them. I think a big benefit of compiling is slightly faster startup, but it is not worth spending hours compiling such a big package when binary versions are available.

I have been trying out using a zram mounted /tmp, and have allocated 500M to it. I have made my browser cache go to the /tmp and have never seen the usage go above 50M.
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