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by swampdog
Fri Nov 29, 2019 10:01 am
Forum: Raspbian
Topic: lvm: pvmove crashed, how to recover?
Replies: 12
Views: 361

Re: lvm: pvmove crashed, how to recover?

The first thing to do would be to try and recover the mdadm RAID array. Then look at resuming the pvmove. We'll have to wait for the OP. I'm not sure there is a software raid.. [ 15.565790] device-mapper: raid: Failed to read superblock of device at position 2 [ 15.601120] md/raid:mdX: not clean --...
by swampdog
Fri Nov 29, 2019 8:39 am
Forum: Raspbian
Topic: lvm: pvmove crashed, how to recover?
Replies: 12
Views: 361

Re: lvm: pvmove crashed, how to recover?

I'll admit I've never used LVM RAID by itself. I've always used LVM on top of MD which handled the RAID side of things. Yep. It's unusual. I've just found some info on redhat site. Since rhel 6.3 the default changed away from "segment type mirror" to "segment type raid1" so it will depend what inst...
by swampdog
Fri Nov 29, 2019 7:54 am
Forum: Raspbian
Topic: lvm: pvmove crashed, how to recover?
Replies: 12
Views: 361

Re: lvm: pvmove crashed, how to recover?

Do not use raid5. It needs four drives and only one can fail. RAID 5 requires a minimum of three drives of which at least two need to be operational for the data to be accessible. Depending how LVM is configured an extra drive may be required for logging (--mirrorlog). I'm playing it safe because w...
by swampdog
Fri Nov 29, 2019 6:05 am
Forum: Raspbian
Topic: lvm: pvmove crashed, how to recover?
Replies: 12
Views: 361

Re: lvm: pvmove crashed, how to recover?

My system consists of rasberry pi 4 with raspian using the 64bit kernel I'd suspect the 64bit kernel.. [ 9667.686238] INFO: task usb-storage:176 blocked for more than 120 seconds. ..or your usb adapter. I'm afraid if you really wanted this data you should have not gone bleeding edge and done more t...
by swampdog
Thu Nov 28, 2019 2:57 am
Forum: Networking and servers
Topic: AM I defaulting to a degraded Raid5 array?
Replies: 16
Views: 664

Re: AM I defaulting to a degraded Raid5 array?

Deathstars? I guess you could call contracting for a public body a deathstar. :-) rpdom is talking about the disasterous IBM Deskstar hard disks from around 2000. One particular HD had an incredibly high failure rate and caused the name IBM Deathstar to be coined. If your HD died then it was disast...
by swampdog
Thu Nov 28, 2019 2:24 am
Forum: C/C++
Topic: Linaro armv8l-linux-gnueabihf compiler
Replies: 2
Views: 231

Re: Linaro armv8l-linux-gnueabihf compiler

Nothing obvious looking at the linaro website so you'll probably have to look at the source for the configs. This *might* help..

Code: Select all

gcc -v --help 2>&1 | less
gcc -march=native -Q --help=target | less
..replacing 'gcc' accordingly.
by swampdog
Thu Nov 28, 2019 1:56 am
Forum: C/C++
Topic: Raspi 4b reserve core for C++
Replies: 30
Views: 1408

Re: Raspi 4b reserve core for C++

Can't remember how to use it but here you go.. admin@pi05:~ $ apropos affinity pthread_attr_getaffinity_np (3) - set/get CPU affinity attribute in thread at... pthread_attr_setaffinity_np (3) - set/get CPU affinity attribute in thread at... pthread_getaffinity_np (3) - set/get CPU affinity of a thre...
by swampdog
Thu Nov 28, 2019 1:50 am
Forum: Networking and servers
Topic: AM I defaulting to a degraded Raid5 array?
Replies: 16
Views: 664

Re: AM I defaulting to a degraded Raid5 array?

rpdom wrote:
Wed Nov 27, 2019 6:19 am
swampdog wrote:
Wed Nov 27, 2019 2:59 am
Last reasonably big place I worked at, it was the "nobody ever got sacked for buying ibm" mantra.
Deathstars?
I guess you could call contracting for a public body a deathstar. :-)
by swampdog
Wed Nov 27, 2019 3:33 am
Forum: Raspbian
Topic: Multiple rpi3 gone offlien on the lan at the same minute definitively
Replies: 3
Views: 202

Re: Multiple rpi3 gone offlien on the lan at the same minute definitively

I would check the dhcp lease first. $ sudo cat /var/log/syslog | egrep -i dhcp ..possibly "syslog.1" or older files. Also check your dhcp server logs - as everything went wrong at the same time it was probably that which caused the problem. For example, when my ISP does a firmware update on our cabl...
by swampdog
Wed Nov 27, 2019 2:59 am
Forum: Networking and servers
Topic: AM I defaulting to a degraded Raid5 array?
Replies: 16
Views: 664

Re: AM I defaulting to a degraded Raid5 array?

Typically you purchase all the disks at the same time and they get used evenly so when one fails the others are eol: the unusual effort of resyncing all the sectors quite often causes one of the remaining ones to drop out. We had that happen a few times back in the days when I worked with big serve...
by swampdog
Sat Nov 23, 2019 1:43 am
Forum: Networking and servers
Topic: AM I defaulting to a degraded Raid5 array?
Replies: 16
Views: 664

Re: AM I defaulting to a degraded Raid5 array?

If you can afford another one, buy another disk and use raid6 because raid5 has a nasty habit of failing twice in a row. You'll have less space (twice size of disk total) but can have two disks fail. raid5 was never designed for disks the size of current offerings. Typically you purchase all the dis...
by swampdog
Sat Nov 23, 2019 12:39 am
Forum: Beginners
Topic: Virtual Disk Management (Mirroring)
Replies: 4
Views: 231

Re: Virtual Disk Management (Mirroring)

I've been using LVM (Logical Volume Manager) on my rpi4 without issue. It supports mirroring and there's no reason mirroring wouldn't work because it's just a component of LVM. Setting up LVM is not trivial. You'll need an "initrd" if you want to boot using it and that means you'll need a custom upd...
by swampdog
Fri Nov 22, 2019 11:43 pm
Forum: Raspbian
Topic: Buster on Pi 4 4GB and some issues
Replies: 6
Views: 571

Re: Buster on Pi 4 4GB and some issues

I'm almost certainly about to write a useless post as I have almost no information. I took my Pi4 to Blackpool and had the same issue at the place we were staying at. The only info I have is the TV was "Veltech", firmware V0.01 2018-04-10 23:38:13" which appears to be some generic "thing" no longer ...
by swampdog
Fri Nov 22, 2019 11:03 pm
Forum: C/C++
Topic: [solved] access dynamic multidimensional arrays like static arrays
Replies: 24
Views: 1147

Re: access dynamic multidimensional arrays like static arrays

Thank you a lot, swampdog, but hell, that is really sophisticated stuff, far beyond by skills :shock: tbh, I was hoping to get sth like the new() thing from above (https://www.raspberrypi.org/forums/viewtopic.php?f=33&t=257284&p=1570009#p1569630), but now compatible both for gcc and g++ compilers, ...
by swampdog
Fri Nov 22, 2019 1:12 pm
Forum: C/C++
Topic: [solved] access dynamic multidimensional arrays like static arrays
Replies: 24
Views: 1147

Re: access dynamic multidimensional arrays like static arrays

This kind of approach is more like the C++ way. Of necessity, it is far from complete - you'll need a decent C++ tutorial forum for that but does outline what is possible and hints what needs to be covered to get something functional. What follows is more along the lines of an academic exercise. In ...
by swampdog
Thu Nov 21, 2019 5:59 pm
Forum: C/C++
Topic: [solved] access dynamic multidimensional arrays like static arrays
Replies: 24
Views: 1147

Re: access dynamic multidimensional arrays like static arrays

You can muck about but this is the area where it is extremely easy to corrupt memory.. #include <stdio.h> #include <stdlib.h> #include <string.h> #define X 10 #define Y 5 typedef struct { double a[X][Y]; } FOO; static void dump(double a[X][Y]) {size_t x,y; for(x=0;x<X;x++) { for(y=0;y<Y;y++) printf(...
by swampdog
Fri Nov 15, 2019 9:20 pm
Forum: Advanced users
Topic: SSH with RSA keys for MPI cluster
Replies: 4
Views: 270

Re: SSH with RSA keys for MPI cluster

You probably need to elaborate. Note though, it is possible to use the same set of keys all over the place. Typically this is one of those "d'Oh!" moments when someone clones and ships a preconfigured machine and *hasn't* cleared the keys but can be used to good effect if thought out.
by swampdog
Fri Nov 15, 2019 9:02 pm
Forum: Troubleshooting
Topic: RAID5: Remove all drives prevents boot
Replies: 6
Views: 305

Re: RAID5: Remove all drives prevents boot

As a side-issue, with large disks in enterprise environments, raid5 has a habit of dropping dead during the rebuild. What happens is all the disks are inserted into the SAN (storage area network, aka NAS) on day one. Much time later one fails. By that time all the disks are about to fail: the resync...
by swampdog
Fri Nov 08, 2019 7:29 pm
Forum: Raspbian
Topic: Raspbian cross toolchain
Replies: 8
Views: 916

Re: Raspbian cross toolchain

It really isn't worth it (cross compiling). Certainly now. Once the final product is ready, build it natively on an rpi or just get an rpi4 with an approved psu and a fan and develop it natively. If your project needs rpi features then you'll need to be developing some of it natively and if your pro...
by swampdog
Fri Nov 08, 2019 6:36 pm
Forum: Troubleshooting
Topic: rsync to/from remote server - no password
Replies: 19
Views: 1454

Re: rsync to/from remote server - no password

There's three potential hurdles. (a) ensure the source "src" box can 'ssh' into the destination "dst" box without a password. (b) unix file permissions. (c) keeping it simple but with a mind to security. Take user "foo" on "src" wants to copy root files to "dst".. foo@src $ sudo id ^^^if that works ...
by swampdog
Mon Oct 28, 2019 12:23 am
Forum: Advanced users
Topic: Moving file system to NFS share - not working - nfs server not responding
Replies: 14
Views: 1882

Re: Moving file system to NFS share - not working - nfs server not responding

I missed this thread originally. On the off-chance it might help narrowing it down.. admin@pi05:~ $ cat /boot/cmdline.txt dwc_otg.lpm_enable=0 console=serial0,115200 console=tty1 root=/dev/nfs smsc95xx.turbo_mode=N nfsroot=192.168.1.20:/mnt/nfsd/pi05,tcp,vers=3 ip=::::pi05.swampdog::dhcp rootfstype=...
by swampdog
Sun Oct 27, 2019 11:45 pm
Forum: Beginners
Topic: Maria DB: Installation of system tables failed!
Replies: 14
Views: 873

Re: Maria DB: Installation of system tables failed!

I built mariadb 5.5.56 for an rpi3 from source a couple of years ago. It still fires up.. admin@pi05:~/usr/src/mariadb $ sudo ./svr-mysql start admin@pi05:~/usr/src/mariadb $ ps -ef | grep mysql root 30210 1 0 23:07 pts/0 00:00:00 /bin/sh /usr/local/MARIADB/5556/bin/mysqld_safe --no-defaults --user=...
by swampdog
Sun Oct 27, 2019 8:28 pm
Forum: C/C++
Topic: Unable to find libpng and harfbuzz when compiling SDL2 TTF Library
Replies: 2
Views: 2952

Re: Unable to find libpng and harfbuzz when compiling SDL2 TTF Library

I'm going from memory here (years ago back when I built SDL under cygwin). I think SDL uses 'pkg-config' so try asking it what linker flags are required (eg: pkg-config --libs libpng16) then fudge those flags into your makefile (LDFLAGS?). If there was a 'configure' script then the bug is there beca...
by swampdog
Sat Oct 19, 2019 11:33 pm
Forum: C/C++
Topic: cc: error trying to exec '/usr/lib/gcc/arm-linux-gnueabihf/8/cc1'
Replies: 2
Views: 1309

Re: cc: error trying to exec '/usr/lib/gcc/arm-linux-gnueabihf/8/cc1'

$ sudo apt-get install apt-file $ apt-file update $ apt-file search /usr/lib/gcc/arm-linux-gnueabihf/8/cc1 Results likely to be.. cpp-8: /usr/lib/gcc/arm-linux-gnueabihf/8/cc1 g++-8: /usr/lib/gcc/arm-linux-gnueabihf/8/cc1plus gdc-8: /usr/lib/gcc/arm-linux-gnueabihf/8/cc1d gobjc++-8: /usr/lib/gcc/ar...
by swampdog
Fri Oct 11, 2019 11:29 pm
Forum: C/C++
Topic: copy protect an application
Replies: 3
Views: 1078

Re: protect an application

If your Pi always has access to a network then you could implement something reasonably secure. It will never be foolproof though. The only way to do that is manually type in the password to decrypt (eg: like "tails" on a usb stick) the filesystem. Mac address can be spoofed of course. That aside, t...

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