Re: Linux Disk Performance

Ernst Lobsiger
 

Hi Olivier

Welcome to the small troop of amateurs that use GNU/Linux for
EUMETCast. Nice to hear that you got it working on Linux Mint.

/dev/sdb1 is a device file meaning partition 1 on your second disk

You mount /dev/sdb1 tt an appropriate mount point
(directory) in your root file system / that apparently
resides on your SSD /dev/sda? ... If you type just "mount" in
a terminal you see how it's all assebled. Your SSD may also
be partitioned in /dev/sda1 (SWAP) and /dev/sda2 / (root) ...

Your mount point seems to be /media/ops/EUMETCast
So if /dev/sdb1 is not mounted, /media/ops/EUMETCast
is just a directory on your SSD that you can use as
far as you have access rights. As soon as /dev/sdb1
is mounted here, writing to this directory means
writing to (the top most place of) your big disk.

In Linux you *MUST* have the EUMETCast tmp directory and the
final received files on the same file system (partition). In
your case everything either on SSD (which will wear out and
overfill faster than you like it ...) or on your hopefully
fast enough second HDD. So forget your idea of

sudo mount -t tmpfs -o size=2048M tmpfs /media/ops/EUMETCast/ramdisk

This makes a tmp file system in memory that you give a mount point
on your second HDD which is already mouted on your SSD. Not KISS.
A tmpfs is not even a RAM disk as expected as it swaps out data
blocks that have not been touched for some time to your SWAP device.

Just for whatever channels an entry (I made ist already shorter :-)

target_directory=/media/ops/EUMETCast/bas/data/default
tmp_directory=/media/ops/EUMETCast/bas/tmp

This should work though I have my paths much more flat
and mount the data HDD as just /srv (or /opt or /mnt)

Soon you will want to slice your data in channel directories.


Cheers
Ernst

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