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1  Linux Stuff / General Linux questions / Re: Storage for Database on: December 12, 2010, 06:06:13 AM
Thanks for your info. It was very helpfull.
I checked some tech info and SD didn't seem so fast.
The only spec's I could find was MB/s and just as a comparisson:
- SD card / SSD: 6 MB/s
- NFS: 1 Gbit/sec??? (about 128 MB/sec)
- USB harddisk: 480 Mbit/s (about 60MB/s)
- ESATA: 3 Gbit/sec (about 375 MB/s)

But 'no spin time' could indeed be a big accelerator for small reads.
By the way, I forgot one option.
My NAS also support iSCSI.
I have a GB lan, so it could be quite fast.
I will check out SD card, NFS, iSCSI and USB harddisk somewhere next week.
I'll let you know some results.
2  Linux Stuff / General Linux questions / Re: Write to microSD with LAMP (www-data) on: December 12, 2010, 01:17:40 AM
I have a normal SD card inserted.
It was auto-mounted on /media/usb0.
What I did was:
    sudo mkdir /media/usb0/test
    sudo chmod 777 /media/usb0/test

The command 'sudo -u www-data touch /media/usb0/test/test' gives the following error:
   touch: cannot touch `/media/usb0/test/test': Permission denied

So I think I have the same issue as you have.
The command 'mount' tells: about this mount:
    /dev/sdb1 on /media/usb0 type vfat (rw,noexec,nodev,sync,noatime)

The command 'ls -alth /media/usb0/test/' tells me:
    total 32K
    drwxr-xr-x 2 root root 16K 2010-12-12 07:38 .
    drwxr-xr-x 4 root root 16K 2010-12-12 07:38 ..
So chmod did not change permissions.

I experienced this behaviour in the past and if I remember correctly,
the thing is that vfat is designed for Windows permissions.
And linux permissions and Windows permissions quite different.
Therefore setting Linux permissions on a vfat mount (sub path) does not work.
What you can do is set linux permissions and ownership for the whole tree.
You can specify this in your mount command (not with automount, I guess).
check 'man mount' for more info.
Or you might change to a linux filesystem such as ext2

I'm not a Linux guru myselve, but I hope I helped you in the right direction.
Greetz Smiley
3  Linux Stuff / General Linux questions / Storage for Database on: December 11, 2010, 06:02:09 AM
I just bought a Guruplug server.
I'm quite happy with it.  Smiley
It makes more noise than a regular airport and that's an issue, but other than that i's a neat device.
Anyway, I'm looking into serving databases from it. MySQL and / or Postgres.
I was thinking about where to place the database files.
In my situation I have multiple options:
- Micro SD, but it's slow (6MB/s) and has about 10.000 writes.
  A database server writes a lot, and you don't want a corrupt storage location for database files.
- Internal storage, but it's only 512 MB for everything, leaving little space for database files.
  And same thing goed as for MicroSD, Slow and only 10.000 writes.
  And i'd rather waer out MicroSD card than internal Flash.
- NAS (NFS), but it is still quite slow and not recommended by PostGres. For MySQL soma are more positive than others.
 General opinion is don't use NFS for databases
- USB harddisk: I have one, but it's USB 2.0. Not so fast (faster than MicroSD and probably faster than NAS too, but neverthless).
  And on top of that, i'm already using it for other stuff.
- Buy a harddisk. USB 3.0 might do the trick, but eSATA is fasther. SSD might be a better option.
  However, than I would have two devices instead of one, using more energy, taking up more space and I have to buy something.  Cry

I don't do rocket science so I don't need the fastest sollution. But I'd like to choose the best option.
Has anyone of you any idea about what would be best te server my needs?
Do you have any experience with MicroSD, NFS, etc?
Please let me know if you do.

I'm looking forward to hearing from you.
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