I would like to start screen detached session, but I want to evaluate some bash. It seems screen only supports an executable and binary. I want do do some magic like:
screen -d -m script.sh 2>&1 | tee logfile.log
but this apparently does not work. Quoting does not help here. The only idea I have is to create a wrapper script that will do this redirection and then to call it directly, like:
screen -d -m wrapper_script.sh
Any other ideas? Thanks.
Helli,
I have a script that waits some time until a machine (being provisioned) comes up and then it connects to ssh and executes something. I use "sleep" for that.
I would like change my script to actively check the port in a bash loop and when it's ready (sshd is started and accepting connections) it would continue.
How to do that? Is there an UNIX command that is able to tell me if the TCP server port is responding?
I created a virtual NAT network (192.168.100.0/24 network) in my libvirt and new guest with two interfaces - one in this network, one as bridged (10.34.1.0/24 network) to the local LAN. The reason for that is I need to have my own virtual network for my DHCP/TFTP/DNS testing and still want to access my guest externally from my LAN. On both networks I have working DHCP, both giving them IP addresses.
When I setup NAT port forwarding (e.g. for ssh), I can connect to the eth0 (virtual network), everything is fine.
But when I try to access the eth1 via bridged interface, I have no response. I guess I have problem with my routing table - outgoing packets are routed to the virtual NAT network (which has access to the machine I am connecting from - I can ping it). But I am not sure if this setup is correct. I think I need to add something to my routing table.
# ifconfig
eth0 Link encap:Ethernet HWaddr 52:54:00:B4:A7:5F
inet addr:192.168.100.14 Bcast:192.168.100.255 Mask:255.255.255.0
inet6 addr: fe80::5054:ff:feb4:a75f/64 Scope:Link
UP BROADCAST RUNNING MULTICAST MTU:1500 Metric:1
RX packets:16468 errors:0 dropped:27 overruns:0 frame:0
TX packets:6081 errors:0 dropped:0 overruns:0 carrier:0
collisions:0 txqueuelen:1000
RX bytes:22066140 (21.0 MiB) TX bytes:483249 (471.9 KiB)
Interrupt:11 Base address:0x2000
eth1 Link encap:Ethernet HWaddr 52:54:00:DE:16:21
inet addr:10.34.1.111 Bcast:10.34.1.255 Mask:255.255.255.0
inet6 addr: fe80::5054:ff:fede:1621/64 Scope:Link
UP BROADCAST RUNNING MULTICAST MTU:1500 Metric:1
RX packets:34 errors:0 dropped:0 overruns:0 frame:0
TX packets:189 errors:0 dropped:0 overruns:0 carrier:0
collisions:0 txqueuelen:1000
RX bytes:4911 (4.7 KiB) TX bytes:9
# route -n
Kernel IP routing table
Destination Gateway Genmask Flags Metric Ref Use Iface
192.168.100.0 0.0.0.0 255.255.255.0 U 0 0 0 eth0
10.34.1.0 0.0.0.0 255.255.255.0 U 0 0 0 eth1
169.254.0.0 0.0.0.0 255.255.0.0 U 1002 0 0 eth0
169.254.0.0 0.0.0.0 255.255.0.0 U 1003 0 0 eth1
0.0.0.0 192.168.100.1 0.0.0.0 UG 0 0 0 eth0
Network I am trying to connect from is different than network the hypervisor is connected to: 10.36.0.0. But it is accessible from that network. So I tried to add new route rule:
route add -net 10.36.0.0 netmask 255.255.0.0 dev eth1
And it is not working. I thought setting correct interface would be sufficient. What is needed to get my packets coming through?
I played with spindown and APM settings of my Samsung discs and now they spin down every minute. I want to disable it, but it seems it does not accept any of the spindown time or APM values. Nothing works, it's all the same.
Please help what values should be proper for it. I do not want it to spin down at all.
/dev/sda:
ATA device, with non-removable media
Model Number: SAMSUNG HD154UI
Serial Number: S1Y6J1KZ206527
Firmware Revision: 1AG01118
Standards:
Used: ATA-8-ACS revision 3b
Supported: 7 6 5 4
Configuration:
Logical max current
cylinders 16383 16383
heads 16 16
sectors/track 63 63
--
CHS current addressable sectors: 16514064
LBA user addressable sectors: 268435455
LBA48 user addressable sectors: 2930277168
Logical/Physical Sector size: 512 bytes
device size with M = 1024*1024: 1430799 MBytes
device size with M = 1000*1000: 1500301 MBytes (1500 GB)
cache/buffer size = unknown
Capabilities:
LBA, IORDY(can be disabled)
Queue depth: 32
Standby timer values: spec'd by Standard, no device specific minimum
R/W multiple sector transfer: Max = 16 Current = 16
Advanced power management level: 60
Recommended acoustic management value: 254, current value: 0
DMA: mdma0 mdma1 mdma2 udma0 udma1 udma2 udma3 udma4 udma5 *udma6 udma7
Cycle time: min=120ns recommended=120ns
PIO: pio0 pio1 pio2 pio3 pio4
Cycle time: no flow control=120ns IORDY flow control=120ns
Commands/features:
Enabled Supported:
* SMART feature set
Security Mode feature set
* Power Management feature set
* Write cache
* Look-ahead
* Host Protected Area feature set
* WRITE_BUFFER command
* READ_BUFFER command
* NOP cmd
* DOWNLOAD_MICROCODE
* Advanced Power Management feature set
Power-Up In Standby feature set
* SET_FEATURES required to spinup after power up
SET_MAX security extension
Automatic Acoustic Management feature set
* 48-bit Address feature set
* Device Configuration Overlay feature set
* Mandatory FLUSH_CACHE
* FLUSH_CACHE_EXT
* SMART error logging
* SMART self-test
Media Card Pass-Through
* General Purpose Logging feature set
* 64-bit World wide name
* WRITE_UNCORRECTABLE_EXT command
* {READ,WRITE}_DMA_EXT_GPL commands
* Segmented DOWNLOAD_MICROCODE
* Gen1 signaling speed (1.5Gb/s)
* Gen2 signaling speed (3.0Gb/s)
* Native Command Queueing (NCQ)
* Host-initiated interface power management
* Phy event counters
* NCQ priority information
DMA Setup Auto-Activate optimization
Device-initiated interface power management
* Software settings preservation
* SMART Command Transport (SCT) feature set
* SCT Long Sector Access (AC1)
* SCT LBA Segment Access (AC2)
* SCT Error Recovery Control (AC3)
* SCT Features Control (AC4)
* SCT Data Tables (AC5)
Security:
Master password revision code = 65534
supported
not enabled
not locked
frozen
not expired: security count
supported: enhanced erase
326min for SECURITY ERASE UNIT. 326min for ENHANCED SECURITY ERASE UNIT.
Logical Unit WWN Device Identifier: 50024e900300cca3
NAA : 5
IEEE OUI : 0024e9
Unique ID : 00300cca3
Checksum: correct
I have the very same disc which I did not "tuned" and it does not spin. But I do not know where to read the settings from. The hdparm only shows this:
Advanced power management level: 60
Recommended acoustic management value: 254, current value: 0
Edit: It seems the issue was tuned daemon in RHEL6. It was too aggressive, I turned off disc tuning and it seems they are no longer spinning down.
I am able to set both APM and spindown times using the command:
hdparm -S 246 -B 128 /dev/sda
Unfortunately I can only find the APM value in the information output:
hdparm -I /dev/sda | grep Advanced
How can I see the spindown time value? I suspect my disc it is ignoring my value. I would like to see it. Tried smartctl but with no luck, help.
Update: It turned out tuned is very aggressive. When I turned it down, my discs does not spin down. It was setting something there.