I'm after getting a small SSD to boot my Pi 4 from, instead of from the
micro SD.
Buying USB sticks and drives is fraught with danger from fake devices so
can anyone recommend a supplier? I don't need any spare space so even a
32Gb SSD would be fine but nowadays 128Gb is almost as cheap.
On Thu, 13 Jan 2022 17:54:52 +0000, Chris Green wrote:
I'm after getting a small SSD to boot my Pi 4 from, instead of from the micro SD.
Buying USB sticks and drives is fraught with danger from fake devices so can anyone recommend a supplier? I don't need any spare space so even a 32Gb SSD would be fine but nowadays 128Gb is almost as cheap.
I've been using a 128GB Sandisk SSD for the last 5 years without any problems, though it is SATA connected rather than USB, but I see they
also sell USB connected 128 GB SSD devices. They're also my preferred SD
card supplier.
If you install an SSD drive, do install and use "fstrim -a -v" as a
weekly cron job to keep the SSD's block structure tidy.
So what does 'discard' mean in this context? An 'unused block' is
surely just that, how can you discard it? Or does it mean that it
discards blocks allocated because the minimum allocation by the OS is
larger than the actual device block size?
... and further, it's run automatically by systemd on my systems.
I'm after getting a small SSD to boot my Pi 4 from, instead of from
the micro SD.
Buying USB sticks and drives is fraught with danger from fake devices
so can anyone recommend a supplier? I don't need any spare space so
even a 32Gb SSD would be fine but nowadays 128Gb is almost as cheap.
On Thu, 13 Jan 2022 18:49:29 +0000, Chris Green wrote:
So what does 'discard' mean in this context? An 'unused block' isPass. My guess is that it compacts and possibly reorders the free block chain. However, I don't understand why they'd calling that 'discarding' blocks since no blocks are actually discarded, i.e. marked unusable.
surely just that, how can you discard it? Or does it mean that it
discards blocks allocated because the minimum allocation by the OS is
larger than the actual device block size?
... and further, it's run automatically by systemd on my systems.
Fairy Snuff. It wasn't on my system, an old Lenovo R61i running Fedora
Linux, where it replaced a 120GB HDD when that died.
Martin Gregorie <martin@mydomain.invalid> wrote:
If you install an SSD drive, do install and use "fstrim -a -v" as a
weekly cron job to keep the SSD's block structure tidy.
Doesn't it tend to second guess the SSD's own wear levelling? Looking
at the man page I'm not at all clear what it does:-
fstrim is used on a mounted filesystem to discard (or "trim")
blocks which are not in use by the filesystem...
So what does 'discard' mean in this context? An 'unused block' is
surely just that, how can you discard it? Or does it mean that it
On 13/01/2022 17:54, Chris Green wrote:
I'm after getting a small SSD to boot my Pi 4 from, instead of from
the micro SD.
Buying USB sticks and drives is fraught with danger from fake devices
so can anyone recommend a supplier? I don't need any spare space so
even a 32Gb SSD would be fine but nowadays 128Gb is almost as cheap.
After a duff initial one Ive specialised in Kingston SSDS BOUGHT FROM KINGSTON. Any Chinese knock off can have a Kingston sticker on it
Smallest they do these days is 120GB for £22.75 UK sterling price
https://www.kingston.com/unitedkingdom/en/ssd/a400-solid-state-drive#atc
Of course that will need a USB to SATA adapter of some sort
On Thu, 13 Jan 2022 18:49:29 +0000, Chris Green wrote:
So what does 'discard' mean in this context? An 'unused block' is
surely just that, how can you discard it? Or does it mean that it
discards blocks allocated because the minimum allocation by the OS is larger than the actual device block size?
Pass. My guess is that it compacts and possibly reorders the free block chain. However, I don't understand why they'd calling that 'discarding' blocks since no blocks are actually discarded, i.e. marked unusable.
... and further, it's run automatically by systemd on my systems.
Fairy Snuff. It wasn't on my system, an old Lenovo R61i running Fedora
Linux, where it replaced a 120GB HDD when that died.
I'm after getting a small SSD to boot my Pi 4 from, instead of from
the micro SD.
Buying USB sticks and drives is fraught with danger from fake devices
so can anyone recommend a supplier? I don't need any spare space so
even a 32Gb SSD would be fine but nowadays 128Gb is almost as cheap.
On Thu, 13 Jan 2022 18:49:29 +0000
Chris Green <cl@isbd.net> wrote:
Martin Gregorie <martin@mydomain.invalid> wrote:
If you install an SSD drive, do install and use "fstrim -a -v" as aDoesn't it tend to second guess the SSD's own wear levelling? Looking
weekly cron job to keep the SSD's block structure tidy.
at the man page I'm not at all clear what it does:-
As I understand it fstrim essentially passes hints to the SSD based
on the filesystem layers knowledge of what's going on.
fstrim is used on a mounted filesystem to discard (or "trim")
blocks which are not in use by the filesystem...
So what does 'discard' mean in this context? An 'unused block' is
surely just that, how can you discard it? Or does it mean that it
Once a block has been used there is no way for the SSD to know that
it has become unused unless the filesystem tells the SSD so fstrim exists
to pass that information between the layers.
Martin Gregorie <martin@mydomain.invalid> wrote:
On Thu, 13 Jan 2022 18:49:29 +0000, Chris Green wrote:the more I read about it the less I believe it does anything actually
So what does 'discard' mean in this context? An 'unused block' isPass. My guess is that it compacts and possibly reorders the free block
surely just that, how can you discard it? Or does it mean that it
discards blocks allocated because the minimum allocation by the OS is
larger than the actual device block size?
chain. However, I don't understand why they'd calling that 'discarding'
blocks since no blocks are actually discarded, i.e. marked unusable.
useful.
... and further, it's run automatically by systemd on my systems.
Fairy Snuff. It wasn't on my system, an old Lenovo R61i running Fedora
Linux, where it replaced a 120GB HDD when that died.
On 13/01/2022 17:54, Chris Green wrote:
I'm after getting a small SSD to boot my Pi 4 from, instead of fromAfter a duff initial one Ive specialised in Kingston SSDS BOUGHT FROM KINGSTON. Any Chinese knock off can have a Kingston sticker on it
the micro SD.
Buying USB sticks and drives is fraught with danger from fake
devices so can anyone recommend a supplier? I don't need any spare
space so even a 32Gb SSD would be fine but nowadays 128Gb is almost
as cheap.
Smallest they do these days is 120GB for £22.75 UK sterling price
https://www.kingston.com/unitedkingdom/en/ssd/a400-solid-state-drive#a
tc
Of course that will need a USB to SATA adapter of some sort
So the SSD must take static data and move it to higher wear blocks. All fstrim does it make sure it doesn't do that to *deleted* blocks.
Although unless its a very very busy little disk, I am not sure how
many of those there will actually be.
Thanks, that's just the sort of info I'm after.
On Thu, 13 Jan 2022 20:30:18 +0000, The Natural Philosopher wrote:
So the SSD must take static data and move it to higher wear blocks. AllMy 128GB SSD gets fstrimmed once a week and typically shows that as
fstrim does it make sure it doesn't do that to *deleted* blocks.
Although unless its a very very busy little disk, I am not sure how
many of those there will actually be.
affecting 1-2GB of storage on each run.
This is a machine that doesn't obviously do a lot: its typical weeks
workload is three items:
1) rsync backup (read-only task)
2) weekly dnf update run: its a Fedora box
3) the rest of the time its running the protein Folding At Home
application.
On 13/01/2022 21:41, Martin Gregorie wrote:
This is a machine that doesn't obviously do a lot: its typical weeks
workload is three items:
Does it do log file rotation?
Even my Pis SD card stores log files. It will kill it eventually
I see around 655Mbytes of log files rotated nightly on this machine
(intel desktop with ssd)
On Thu, 13 Jan 2022 22:55:26 +0000, The Natural Philosopher wrote:
On 13/01/2022 21:41, Martin Gregorie wrote:Of course - I've never seen a Linux system that didn't,
This is a machine that doesn't obviously do a lot: its typical weeks
workload is three items:
Does it do log file rotation?
My logfiles are all organised as the current logfile plus the previous 4 generations and managed by the 'logrotate' overnight task, which gets automatically run when the machine is booted if it wasn't running at 1 AM last night or hasn't been run for more than 24 hours.
On 14/01/2022 00:43, Martin Gregorie wrote:
On Thu, 13 Jan 2022 22:55:26 +0000, The Natural Philosopher wrote:
On 13/01/2022 21:41, Martin Gregorie wrote:Of course - I've never seen a Linux system that didn't,
This is a machine that doesn't obviously do a lot: its typical weeks
workload is three items:
Does it do log file rotation?
Log rotation is set up automatically for most installed programs, but
its not if the user enabled rsyslogging for their own program, or has
set up a filter of something to a different file to reduce the amount of
crap in syslog. So its worth checking /var/log for anything that's grown huge.
My logfiles are all organised as the current logfile plus the previous
4 generations and managed by the 'logrotate' overnight task, which gets
automatically run when the machine is booted if it wasn't running at 1
AM last night or hasn't been run for more than 24 hours.
I make sure my nightly Raspberry Pi backups occur after a log rotate, as
that normally accounts for most of the data written. I graph the rsync
stats as the if the amount of data increases considerably, its normally something thrashing the log files, which mean something is wrong.
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