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Linux (Mint flavour) swappiness?

gavreid said:
I've attempted to answer that for you twice already. SSD is faster, nvme much faster than sata. A good hard drive is on a par re reliability.
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The amount of RAM is important wrt write performance. When I first put my PC together I measured the write performance and as I was using a 4 channel NVMe M.2 SSD (1TB EVO 970) it was fast. Imagine my surprise when I got the same figures for my 2*2TB SATA hard discs arranged in RAID 0! Impossible! Then at the back of my mind was 'disc cache'. So I increased the number of bytes written in steps from 500 MB and it wasn't until I exceeded 2GB that the write to the hard discs abruptly slowed down to a more realistic value. So I guess that the Linux O/S has allocated around 2GB from my total 32GB as disk cache. So more RAM is good and if I were say performing photo editing or some such activity that wrote and read large files regularly to disc then using a large RAM cache would be very much faster indeed. It would also mean far fewer writes and maybe only after closing the files.

Cheers,

DV
 
Darth Vader said:
The amount of RAM is important wrt write performance. When I first put my PC together I measured the write performance and as I was using a 4 channel NVMe M.2 SSD (1TB EVO 970) it was fast. Imagine my surprise when I got the same figures for my 2*2TB SATA hard discs arranged in RAID 0! Impossible! Then at the back of my mind was 'disc cache'. So I increased the number of bytes written in steps from 500 MB and it wasn't until I exceeded 2GB that the write to the hard discs abruptly slowed down to a more realistic value. So I guess that the Linux O/S has allocated around 2GB from my total 32GB as disk cache. So more RAM is good and if I were say performing photo editing or some such activity that wrote and read large files regularly to disc then using a large RAM cache would be very much faster indeed. It would also mean far fewer writes and maybe only after closing the files.

Cheers,

DV
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Watch the video I linked above DV, Chris covers caching and, at the end, trustworthiness.
 
gavreid said:
I've attempted to answer that for you twice already. SSD is faster, nvme much faster than sata. A good hard drive is on a par re reliability.
Click to expand...

Apologies, and I admit that I got bored with the video before it got to the nitty-gritty regarding reliability. But all clear now, thanks!
 
Many branded PCs are sold with only one large RAM stick. Better CPUs (I5 and above) have two RAM lanes and double memory bandwidth if you fit a second memory module in the correct slot
 
In recent years there have been many problems with flash memory degredation in commercial applications. It has been a problematic phenomenon in everything from enterprise pdas to datacentre switching fabrics where poor operating system code has been hammering the flash with millions of trivial write operations and over time this degrades the memory. Low level routines embedded in the flash controllers are designed to detect and hide bad sectors, but can only work upto a point.

Flash memory is capable of finite write operations, bigger capacity is better, quad layer is cheaper because it is inherently less robust. But for a typical personal computer user an SSD is likely to outlive the utiity of the machine it sits in. Having said that, running OS on one SSD and storing your valuable data on another is probably a good idea. And backup, people, always backup. A wise man (or maybe a diskdrive salesman) told us long ago, you haven't stored your data until you have done so twice.
 
gavreid said:
This explains some of the subtleties about SSDs

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That is a very interesting video and enough to put me off QLC. I have two 1TB SSDs, one in the MacBook Pro and one as a CCC backup (I also have a conventional HD backup). Both my SSDs are Crucial and I assume TLC, though the first one may even be old enough to be MLC (edit: yes, the older M550 is MLC). I don’t entirely trust them hence having multiple backups. I’ll look into the swap file later. The MBP has 16GB RAM and I seldom use it for more than pfm stuff/accounting these days so hopefully its not battering the installed SSD.

I’d still argue SSD is pretty reliable long-term as there are just so many old but perfectly functional iPhones, iPads etc out there and they have to be swapping like crazy given the small amount of RAM available.
 
gavreid said:
His channel is very good, if you can get past the style of the presentation. He has quite a varied interest coming from an academic background
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Yes, I’ve found it previously and watched a fair few of his videos on the Pi etc. YouTube really is wonderful for us geeks, so much good content!
 
This thread has terrified me! The only conclusion is that everything of permanent importance, written texts, documents, photographs, certificates, contracts, should be "backed up" as hard copy. i.e Paper. In the long run, 10, 20, 100 years, all the digital back up is seriously at risk. Indeed, doomed. Maybe it would be wise to use computers only as temporary data management devices.
 
PaulMB said:
This thread has terrified me! The only conclusion is that everything of permanent importance, written texts, documents, photographs, certificates, contracts, should be "backed up" as hard copy. i.e Paper. In the long run, 10, 20, 100 years, all the digital back up is seriously at risk. Indeed, doomed. Maybe it would be wise to use computers only as temporary data management devices.
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I don’t agree. Data is fine as long as it exists in multiple locations, i.e. just have multiple backups, and keep migrating to new physical hardware every now and again and you should be fine. I consider myself safe with the SSD in my MBP, SSD backup and another alternative backup to a conventional HDD. Any two can fail, and that is very unlikely!

Things will get even better if the UK broadband infrastructure ever catches up with other parts of the world and we can start taking cloud computing more seriously (currently the upload speeds are just too slow).
 
Beware data fade on an archived hard drive though. You do need to refresh the data every now and again - you can debate how often that is, but I won't ;)
 
Computer data is just like paper records. As long as the owner is interested in it it can be maintained. After they are gone it is rapidly discarded unless they are of particular significance at that time. An example of this is how much of Shakespeares material was lost soon after his death before he was rediscovered
 
PaulMB said:
This thread has terrified me! The only conclusion is that everything of permanent importance, written texts, documents, photographs, certificates, contracts, should be "backed up" as hard copy. i.e Paper. In the long run, 10, 20, 100 years, all the digital back up is seriously at risk. Indeed, doomed. Maybe it would be wise to use computers only as temporary data management devices.
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There is a new kid on the block but a little more expensive M-Disc. It supposedly has a 1000 year life. Its a type of optical disc but the higher power laser cuts into 'stone' yeah and thats supposed to last 10,000 years however the polymer coating limits this to around 1000 years.

I wonder if there will be any players around?

Cheers,

DV
 
Darth Vader said:
There is a new kid on the block but a little more expensive M-Disc. It supposedly has a 1000 year life. Its a type of optical disc but the higher power laser cuts into 'stone' yeah and thats supposed to last 10,000 years however the polymer coating limits this to around 1000 years.

I wonder if there will be any players around?

Cheers,

DV
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Miniscule capacity though - suppose you could archive your hard drives from 30 years ago, just about ;)
 
I'm not convinced. Tony says you should have multiple back-ups (presumably a mix of DVDs and hard drives or various kinds) and that these should be re-copied to fresh supports periodically. Plus "cloud" so you are relying on someone else to keep things ship-shape for 10 years, 100 years?. David says as long as someone is interested in doing this, which is not much comfort. Hard drives can drop dead, formats will change, burglars steal things, a button pressed by mistake can erase everything. Old photographs, letters, diaries, manuscripts can be put away in an old suitcase and put in an attic. 50 or 100 years later someone turns them up, and in most cases they will be in perfect condition. The durability of ink and paper is incredible. Even old photographs, "analogue" silver gelatin prints, usually survive in good nick for, so far, about 150 years. I recently found photographs of my great-grandparents that had been in a cardboard box for almost that long and were unfaded and free of parasites.

An example: I've got a folder full of letters received from friends, that stops dead around 1995. Nobody actually prints e-mails, and nobody writes them with the idea they will be kept.

Another: I've got loads of photograph albums from about 1880 to the 1990s. After that, nothing.

Any study of an important person of the past, writer, politician, whatever, includes their correspondence and often their diaries. What will historians in 2100 have to work with?
 
gavreid said:
I've attempted to answer that for you twice already. SSD is faster, nvme much faster than sata. A good hard drive is on a par re reliability.
Click to expand...

SSD is also impervious to mechanical schock. In a desktop environment this isn't an issue but when mobile even a relatively small bump can kill a mechanical HD.
 
gavreid said:
Miniscule capacity though - suppose you could archive your hard drives from 30 years ago, just about ;)
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Off shelf up to 128GB Blue Ray at the mo quite a lot of family photos.

Well the first HD I used had a removable platter of 2.5MB thats right MB and was if I remember about 16" across. Over the next 10 years we had migrated to a 52MB HD that could have one to three fixed 13MB platters and a removable 13MB about 20" across. I wrote a disk image copier to back up the fixed platters to up to 3 removable disks. At the time that was quite unique as backup tended to be by 7/8/9 track tape but was slow compared to my bit copier.

In 1000 years time it'll most likely be 3D holograms or some quantum storage.

However M-Disc if its not all hype will see your photos last several generations before a refresh to a newer medium and they also come in several capacities to suit yer pocket.

Amazon sell the M-Disc media in sizes from 4.7 to 100GB and also the BR recorders that cost a bit more that standard due to the inclusion of a higher power laser.

Cheers,

DV
 
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