SSD vs. HDD in Librebooted T400
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Hey there,
I'm looking forward to get myself a librebooted Laptop in the near future and I'm
wondering whether I should go for a big HDD or a small but fast SSD.
I can't really decide for one option and I would like to hear what you would prefer and why.
For me a minimum of 500GB space is required. I can live without a dvd drive but not with less space.
Moreover I would like to hear how the T400 performs without an SSD.
Is it fast enough for typical programming tasks?
I'm looking forward to your ideas and suggestions.
Thanks in advance :-)
Hi :)
For most people, no real performance issues will be noticed with HDDs. Applications are cached in memory during normal operation, for programs that you're running regularly. So if you're usually running a browser and an email client, maybe a few terminals, then you won't really notice any speed issues with HDDs.
SSDs help in terms of boot times, and for non-cached operations (where data is being directly read from or written to the disk, constantly). SSDs are also lighter on power usage, so battery life would be higher.
If storage is a priority, then most 1TB HDDs should do nicely. Minifree sells Libreboot T400 if you're interested; with 1TB HDD, it's currently 248 EUR:
https://minifree.org/product/libreboot-t400/
The best of both worlds is SSD+HDD. The T400 can have 2 storage drives (2nd drive goes in the DVD slot, replacing the DVD drive). So if you wanted extra speed and more storage space, that would be my advice. Minifree also sells that :)
For typical software development, SSD is faster, especially for large programs, since you're writing to / reading from the SSD/HDD a lot.
~Leah
With SSD+HDD, I believe you recommend / on the SSD and /home on the HDD. Any other comment on the partitioning schema? For instance is it advisable to mount /tmp in RAM (ViewTube downloads the videos in /tmp)?
Yes, the default is to use tmpfs (filesystem that exists in RAM) for /tmp
On most typical desktop/laptop based setups, this is a good practise. It doesn't really make any difference in the real world, though.
The difference between SSD and HDD is from night to day.
I doubt programming requires anything specific (I suppose compiling is faster with a strong enough CPU).
SSD as a boot drive will make your boot simply Blitzkrieg. It doesn't help if software is CPU intensive but it makes your executables open faster. Anyway, you'll perceive that everything works double smoothly.
And then there is the issue about swap. Some say you shouldn't use swap on ssd, some say it doesn't matter and some say it isn't even necessary...
It is good to have swap: if a bug makes a program leak memory, the kernel will not kill a random process (well, there is a heuristic) once the RAM is full. Instead, the computer will become unbearably slow (especially if the swap is on HDD) and the user has the time to identify and kill the faulty program. Also, hibernating needs almost as much swap as the RAM that in use. That is why you will often read to set as much swap as RAM. I guess having the swap SSD makes hibernating faster.
Thanks everyone for your input :-).
However one question just came to my mind:
What about full disk encryption?
I heard that SSDs don't like this because the whole drive appears as if it was full and that the SSD can't do wear leveling. Is there any substance to that?
I will use the Laptop primarily on travels for work so i want the data to be encrypted.
I don't know much about hardware as I'm just a scientific software developer but i'd like to learn what you know :-D.
The internal ssd software may undo the effectiveness of the encryption. In german http://www.deutschlandfunk.de/verschluesselungssoftware-veracrypt-unabhaengige.684.de.html?dram:article_id=369309
In my experience, encryption on an SSD doesn't cause any performance issues.
I've been using full disk encryption (including /boot/) on my SSD for a year now with no problems.
The article indeed says that an SSD + encryption causes problems in terms of privacy but they haven't given any source or evidence for this claim.
Even though I'm still not perfectly sure which setup suits my needs best.
Maybe RAID0 with two 1TB HDDs and full disk encryption is the best option for me.
With this i could get faster read/write performance and I'd have 2TB space for my data.
Does anyone have experience with the RAID0 performance on the T400 with full disk encryption?
The CPU will have the overhead for RAID0 and the overhead of encrypting/decrypting data on the fly.
My question is: Will there be a big performance hit?
For instance, wear leveling means that parts of your data might be stored on the drive and you have no way of wiping it, when the controller in the SSD remaps flash cells.
Encrypting that is useful for security purposes. Encryption always (emphasis on the word always) improves your security and privacy (obviously, depending on the key strength, what algorithms you use, what software you use - e.g. luks/dm-crypt).
I use encryption and RAID1 on 2 SSDs (different brands, to avoid having similar MTBF) on my own T400 that I use. I don't notice any real CPU overhead or performance issues with it.
RAID0 or RAID1 on 2 1TB HDDs will also give you a noticeable performance increase, over just 1 HDD. It won't be as fast as an SSD, of course. If you use RAID1, an optimized setup will at least mean that read speeds will be higher, while you get extra guarantee against data loss. I generally recommend RAID1 instead of RAID0 - the performance gain with RAID0 compared to RAID1 isn't actually that much, in the real world, because of how RAID drivers work.
Thank you for your input.
I consider either buying a SSD+HDD-Hybrid or i go for RAID with 2 HDDs.
But I couldn't decide for one of the options yet.
For you, I would probably recommend the SSD for Trisquel (/ and swap), and the 1TB HDD for extra data storage (/home). RAID is only really used in enterprises, where continuous operation is required in the case of disk failure; for simple laptop use-case by domestic users (or non-mission-critical), you'd still have the other drive which you'd be able to re-partition to install Trisquel onto, if one of the drives did fail.
RAID0 on 2 HDDs won't give much performance benefit in practise, and will still fall below SSD speeds.
As long as you keep backups of your data (which is advisable anyway, even with RAID) onto external data, non-RAID is fine for most people. With SSD+HDD, you get the best of both worlds: fast operation for your OS, and vast data storage besides that.
Thanks everyone for your input. I went for a SSD/HDD hybrid and placed my order this weekend.
I'm already excited for my first fully libre PC.
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