user1091344's questions

I have three disks:

• /dev/sda slow hdd
• /dev/sdb slow hdd
• /dev/sdc fast ssd
• /dev/vg0 volume group consisting /dev/sd{a,b,c}

Each logical volume (lv) should be raid1 mirrored and ssd cached.

With the following command, I can create a mirrored raid1 lv named test on vg0.

lvcreate --type raid1 -m 1 -L 1G -n test vg0

• What do I need to change in the previous command so that it will only use the slow hdds for the raid1 mirror? Can I use LVMs tag system (@hdd, @ssd) for this?
• I found some tutorials which explained how to use the LVM cache feature. But it looks like I need to create for each lv an own cache-pool. Is it possible to create one big cache-pool for the whole vg0 so that all lvs in vg0 will be cached? Or can I safely reuse an existing cache-pool for other lvs?

How can I use logger in a shell script?

If I run

ntpd -qnp pool.ntp.org 2> >(logger)

in console, it works as expected.

If I put it into a shell script

#!/bin/sh
ntpd -qnp pool.ntp.org 2> >(logger)

I get following error:

line 2: syntax error: unexpected redirection
exited with code 2

What is wrong in the shell script?

This is very strange. I can not boot up from an USB device until I reboot and close the connection immediately. Then everything works well. I can not provide more information than this, because I don't know more. I don't even know, where I could get logs...

I am regarding to question: Improving IO with FlashCache

I have setup a RAID1 (/dev/md0) LVM (/dev/vg_xen) and executed following command:

flashcache_create -p thru flashcache0 /dev/sdc /dev/md0

Then I started a XEN PV guest, which uses /dev/vg_xen/vm0 as hard disk. After using it a while

cat /proc/flashcache/sdc\+md0/flashcache_stats

shows me

reads=0 writes=0

So, it does not work. What did I do wrong?

I thought that I need two DS records to deposit at my domain registrar. But one big dns provider just gave me one DS record. Verisign DNSSEC debugger says, everything is correct. But I am confused, because dnssec-keygen (DNSSEC key generation tool) gave me always two DS records. I have my doubts.

I have set up some domains with dnssec. I generated the keys and signed the zones with zonesigner from dnssec-tools. I know that I must resign the zones within 30 days. But what's up with the keys which I deposited at my domain provider? Do I need to renew the keys too? If yes, how? Can't find any information about this on the website.