Re: [CentOS] distributed storage/home-made cloud recommendations
-BEGIN PGP SIGNED MESSAGE- Hash: SHA1 Le 04/02/2012 18:39, Boris Epstein a écrit : Hello Laurent, Thanks! Very useful info, I never even heard of MooseFS and it sounds very nice. One question: what happens if you lose your master server in their designation? Or is it possible to make the master server redundant as well? Master HA is not yet possible from moosefs itself. You can use one (or more) metalogger(s) to keep backups of metadata, so you can start another master to replace the failing one. master (ECC ram, redundant psu) never failed here, fingers crossed :) Laurent. -BEGIN PGP SIGNATURE- Version: GnuPG v1.4.11 (GNU/Linux) Comment: Using GnuPG with Mozilla - http://enigmail.mozdev.org/ iEYEARECAAYFAk8uUTgACgkQVObvLNF89kwXrQCglpbx3BG/dWsku1Z3qjoXCcAB x7EAn0NozNyxdXqnVPXzqvwJWxZlYlpj =L60s -END PGP SIGNATURE- ___ CentOS mailing list CentOS@centos.org http://lists.centos.org/mailman/listinfo/centos
Re: [CentOS] configure network bridge listing bridged intefaces
On Saturday 04 February 2012 19:18, the following was written: On 02/03/2012 11:56 PM, Robert Spangler wrote: On Friday 03 February 2012 09:10, the following was written: On 02/03/2012 08:07 AM, Mihamina Rakotomandimby wrote: Hi all, Having a 4 NIC server, I want to bridge eth2 and eth3, with a bridge named br0. Searching the web I only found about creating a file /etc/sysconfig/network-scripts/ifcfg-br0, but did not find where to explicitely list what ports will be bridged. Where is it configured? Thank you. All packets appear on both interfaces, unless you use ebtables/iptables to restrict them. Really? Only hubs present packets to all interfaces. Linux work as a router not a hub. A network bridge connects multiple network segments at the data link layer (Layer 2) of the OSI model. In Ethernet networks, the term bridge formally means a device that behaves according to the IEEE 802.1D standard. A bridge and a switch are very much alike; a switch being a bridge with numerous ports. Switch or Layer 2 switch is often used interchangeably with bridge. The OP was asking for help on configuring bridging. You reply made it sound like it wasn't necessary as All packets appear on both interfaces. That statement is false unless it has been configured that way. Which at that point in time we can assume that the OP hasn't configured it, thus the question. Nice textbook definition btw. -- Regards Robert Linux The adventure of a lifetime. Linux User #296285 Get Counted http://linuxcounter.net/ ___ CentOS mailing list CentOS@centos.org http://lists.centos.org/mailman/listinfo/centos
Re: [CentOS] distributed storage/home-made cloud recommendations
Boris Epstein wrote on 02/04/2012 11:57 AM: What is RAID0+1? Nested RAID. Paraphrasing http://en.wikipedia.org/wiki/RAID : For a RAID 0+1, drives are first combined into multiple level 0 RAIDs that are themselves treated as single drives to be combined into a single RAID 1. Phil ___ CentOS mailing list CentOS@centos.org http://lists.centos.org/mailman/listinfo/centos
Re: [CentOS] distributed storage/home-made cloud recommendations
On Sun, Feb 5, 2012 at 10:32 AM, Phil Schaffner philip.r.schaff...@nasa.gov wrote: Boris Epstein wrote on 02/04/2012 11:57 AM: What is RAID0+1? Nested RAID. Paraphrasing http://en.wikipedia.org/wiki/RAID : For a RAID 0+1, drives are first combined into multiple level 0 RAIDs that are themselves treated as single drives to be combined into a single RAID 1. Phil ___ CentOS mailing list CentOS@centos.org http://lists.centos.org/mailman/listinfo/centos Thanks Phil! ___ CentOS mailing list CentOS@centos.org http://lists.centos.org/mailman/listinfo/centos
Re: [CentOS] mysql won't start with service, but starts with mysqld_safe
On Sat, 2012-02-04 at 17:15 -0700, Larry Martell wrote: Just installed mysql on centos 6.2. When I try to start it with service I get: #service mysqld start MySQL Daemon failed to start. Starting mysqld: [FAILED] Nothing at all is written to the error log. But if I start it with mysqld_safe it comes up and works fine. Anyone know what's going on here? Did it hang while trying to start? Or was it an immediate failure. ___ CentOS mailing list CentOS@centos.org http://lists.centos.org/mailman/listinfo/centos
Re: [CentOS] a cloud VM under CentOS
On Sat, 4 Feb 2012, Digimer wrote: On 02/04/2012 06:15 PM, Boris Epstein wrote: Hello everyone, Does anyone know if it is possible to construct a cloud of sorts out of several CentOS machines so as to enable a VM (or several VM's) that would run on top of that cloud and have failover capability? Boris. Look at Eucalyptus -- Jim Wildman, CISSP, RHCE j...@rossberry.com http://www.rossberry.net Society in every state is a blessing, but Government, even in its best state, is a necessary evil; in its worst state, an intolerable one. Thomas Paine ___ CentOS mailing list CentOS@centos.org http://lists.centos.org/mailman/listinfo/centos
Re: [CentOS] distributed storage/home-made cloud recommendations
On 02/05/2012 04:37 PM, Boris Epstein wrote: On Sun, Feb 5, 2012 at 10:32 AM, Phil Schaffnerphilip.r.schaff...@nasa.gov wrote: Boris Epstein wrote on 02/04/2012 11:57 AM: What is RAID0+1? Nested RAID. Paraphrasing http://en.wikipedia.org/wiki/RAID : For a RAID 0+1, drives are first combined into multiple level 0 RAIDs that are themselves treated as single drives to be combined into a single RAID 1. Google (or other search engine) and Wikipedia are truly a wonder :D -- Ljubomir Ljubojevic (Love is in the Air) PL Computers Serbia, Europe Google is the Mother, Google is the Father, and traceroute is your trusty Spiderman... StarOS, Mikrotik and CentOS/RHEL/Linux consultant ___ CentOS mailing list CentOS@centos.org http://lists.centos.org/mailman/listinfo/centos
Re: [CentOS] mysql won't start with service, but starts with mysqld_safe
On Sun, Feb 5, 2012 at 10:31 AM, Tait Clarridge t...@taiter.com wrote:
On Sat, 2012-02-04 at 17:15 -0700, Larry Martell wrote:
Just installed mysql on centos 6.2. When I try to start it with service I
get:
#service mysqld start
MySQL Daemon failed to start.
Starting mysqld: [FAILED]
Nothing at all is written to the error log.
But if I start it with mysqld_safe it comes up and works fine.
Anyone know what's going on here?
Did it hang while trying to start? Or was it an immediate failure.
Immediate - the 'MySQL Daemon failed to start' message comes out right away.
I was curious as to exactle what 'service mysqld start' did (as
opposed to mysqld_safe, which works) so I traced it. Really didn't
glean anything useful from it - perhaps someone will see something
meaningful:
#strace service mysqld start
execve(/sbin/service, [service, mysqld, start], [/* 20 vars */]) = 0
brk(0) = 0x9873000
mmap2(NULL, 4096, PROT_READ|PROT_WRITE, MAP_PRIVATE|MAP_ANONYMOUS, -1,
0) = 0xb775e000
access(/etc/ld.so.preload, R_OK) = -1 ENOENT (No such file or directory)
open(/etc/ld.so.cache, O_RDONLY) = 3
fstat64(3, {st_mode=S_IFREG|0644, st_size=92683, ...}) = 0
mmap2(NULL, 92683, PROT_READ, MAP_PRIVATE, 3, 0) = 0xb7747000
close(3)= 0
open(/lib/libtinfo.so.5, O_RDONLY)= 3
read(3,
\177ELF\1\1\1\0\0\0\0\0\0\0\0\0\3\0\3\0\1\0\0\0\260\3723\0064\0\0\0...,
512) = 512
fstat64(3, {st_mode=S_IFREG|0755, st_size=99636, ...}) = 0
mmap2(0x633a000, 101528, PROT_READ|PROT_EXEC,
MAP_PRIVATE|MAP_DENYWRITE, 3, 0) = 0x633a000
mmap2(0x635, 12288, PROT_READ|PROT_WRITE,
MAP_PRIVATE|MAP_FIXED|MAP_DENYWRITE, 3, 0x15) = 0x635
close(3)= 0
open(/lib/libdl.so.2, O_RDONLY) = 3
read(3,
\177ELF\1\1\1\0\0\0\0\0\0\0\0\0\3\0\3\0\1\0\0\0`\352\237\0004\0\0\0...,
512) = 512
fstat64(3, {st_mode=S_IFREG|0755, st_size=19784, ...}) = 0
mmap2(0x9fe000, 16500, PROT_READ|PROT_EXEC, MAP_PRIVATE|MAP_DENYWRITE,
3, 0) = 0x9fe000
mmap2(0xa01000, 8192, PROT_READ|PROT_WRITE,
MAP_PRIVATE|MAP_FIXED|MAP_DENYWRITE, 3, 0x2) = 0xa01000
close(3)= 0
open(/lib/libc.so.6, O_RDONLY)= 3
read(3,
\177ELF\1\1\1\3\0\0\0\0\0\0\0\0\3\0\3\0\1\0\0\0@\236\203\0004\0\0\0...,
512) = 512
fstat64(3, {st_mode=S_IFREG|0755, st_size=1876448, ...}) = 0
mmap2(0x823000, 1636744, PROT_READ|PROT_EXEC,
MAP_PRIVATE|MAP_DENYWRITE, 3, 0) = 0x823000
mprotect(0x9ac000, 4096, PROT_NONE) = 0
mmap2(0x9ad000, 12288, PROT_READ|PROT_WRITE,
MAP_PRIVATE|MAP_FIXED|MAP_DENYWRITE, 3, 0x189) = 0x9ad000
mmap2(0x9b, 10632, PROT_READ|PROT_WRITE,
MAP_PRIVATE|MAP_FIXED|MAP_ANONYMOUS, -1, 0) = 0x9b
close(3)= 0
mmap2(NULL, 4096, PROT_READ|PROT_WRITE, MAP_PRIVATE|MAP_ANONYMOUS, -1,
0) = 0xb7746000
mmap2(NULL, 4096, PROT_READ|PROT_WRITE, MAP_PRIVATE|MAP_ANONYMOUS, -1,
0) = 0xb7745000
set_thread_area({entry_number:-1 - 6, base_addr:0xb7746b30,
limit:1048575, seg_32bit:1, contents:0, read_exec_only:0,
limit_in_pages:1, seg_not_present:0, useable:1}) = 0
mprotect(0xa01000, 4096, PROT_READ) = 0
mprotect(0x9ad000, 8192, PROT_READ) = 0
mprotect(0x81b000, 4096, PROT_READ) = 0
munmap(0xb7747000, 92683) = 0
rt_sigprocmask(SIG_BLOCK, NULL, [], 8) = 0
open(/dev/tty, O_RDWR|O_NONBLOCK|O_LARGEFILE) = 3
close(3)= 0
brk(0) = 0x9873000
brk(0x9894000) = 0x9894000
open(/usr/lib/locale/locale-archive, O_RDONLY|O_LARGEFILE) = 3
fstat64(3, {st_mode=S_IFREG|0644, st_size=99158672, ...}) = 0
mmap2(NULL, 2097152, PROT_READ, MAP_PRIVATE, 3, 0) = 0xb7545000
close(3)= 0
getuid32() = 0
getgid32() = 0
geteuid32() = 0
getegid32() = 0
rt_sigprocmask(SIG_BLOCK, NULL, [], 8) = 0
time(NULL) = 1328468051
open(/proc/meminfo, O_RDONLY) = 3
fstat64(3, {st_mode=S_IFREG|0444, st_size=0, ...}) = 0
mmap2(NULL, 4096, PROT_READ|PROT_WRITE, MAP_PRIVATE|MAP_ANONYMOUS, -1,
0) = 0xb775d000
read(3, MemTotal:3741948 kB\nMemF..., 1024) = 1024
close(3)= 0
munmap(0xb775d000, 4096)= 0
rt_sigaction(SIGCHLD, {SIG_DFL, [], 0}, {SIG_DFL, [], 0}, 8) = 0
rt_sigaction(SIGCHLD, {SIG_DFL, [], 0}, {SIG_DFL, [], 0}, 8) = 0
rt_sigaction(SIGINT, {SIG_DFL, [], 0}, {SIG_DFL, [], 0}, 8) = 0
rt_sigaction(SIGINT, {SIG_DFL, [], 0}, {SIG_DFL, [], 0}, 8) = 0
rt_sigaction(SIGQUIT, {SIG_DFL, [], 0}, {SIG_DFL, [], 0}, 8) = 0
rt_sigaction(SIGQUIT, {SIG_DFL, [], 0}, {SIG_DFL, [], 0}, 8) = 0
rt_sigprocmask(SIG_BLOCK, NULL, [], 8) = 0
rt_sigaction(SIGQUIT, {SIG_IGN, [], 0}, {SIG_DFL, [], 0}, 8) = 0
uname({sys=Linux, node=AMAT-centos-6.2, ...}) = 0
getcwd(/usr/local/motor/motor, 4096) = 23
getpid()
Re: [CentOS] configure network bridge listing bridged intefaces
On 02/05/2012 10:17 AM, Robert Spangler wrote: On Saturday 04 February 2012 19:18, the following was written: On 02/03/2012 11:56 PM, Robert Spangler wrote: On Friday 03 February 2012 09:10, the following was written: On 02/03/2012 08:07 AM, Mihamina Rakotomandimby wrote: Hi all, Having a 4 NIC server, I want to bridge eth2 and eth3, with a bridge named br0. Searching the web I only found about creating a file /etc/sysconfig/network-scripts/ifcfg-br0, but did not find where to explicitely list what ports will be bridged. Where is it configured? Thank you. All packets appear on both interfaces, unless you use ebtables/iptables to restrict them. Really? Only hubs present packets to all interfaces. Linux work as a router not a hub. A network bridge connects multiple network segments at the data link layer (Layer 2) of the OSI model. In Ethernet networks, the term bridge formally means a device that behaves according to the IEEE 802.1D standard. A bridge and a switch are very much alike; a switch being a bridge with numerous ports. Switch or Layer 2 switch is often used interchangeably with bridge. The OP was asking for help on configuring bridging. You reply made it sound like it wasn't necessary as All packets appear on both interfaces. That statement is false unless it has been configured that way. Which at that point in time we can assume that the OP hasn't configured it, thus the question. Nice textbook definition btw. Hi Robert, I guess I misread his question - I thought he had the bridge setup and was asking about how to specify what tcp/udp ports would be bridged. My bad. Regards, Steve -- Stephen Clark *NetWolves* Director of Technology Phone: 813-579-3200 Fax: 813-882-0209 Email: steve.cl...@netwolves.com http://www.netwolves.com ___ CentOS mailing list CentOS@centos.org http://lists.centos.org/mailman/listinfo/centos
Re: [CentOS] a cloud VM under CentOS
On Sun, Feb 5, 2012 at 1:25 PM, Jim Wildman j...@rossberry.com wrote: On Sat, 4 Feb 2012, Digimer wrote: On 02/04/2012 06:15 PM, Boris Epstein wrote: Hello everyone, Does anyone know if it is possible to construct a cloud of sorts out of several CentOS machines so as to enable a VM (or several VM's) that would run on top of that cloud and have failover capability? Boris. Look at Eucalyptus -- Jim Wildman, CISSP, RHCE j...@rossberry.com http://www.rossberry.net Society in every state is a blessing, but Government, even in its best state, is a necessary evil; in its worst state, an intolerable one. Thomas Paine ___ CentOS mailing list CentOS@centos.org http://lists.centos.org/mailman/listinfo/centos Jim, thanks. I have come across Eucalyptus and it does look good. I will read more about it. Boris. ___ CentOS mailing list CentOS@centos.org http://lists.centos.org/mailman/listinfo/centos
Re: [CentOS] configure network bridge listing bridged intefaces
On 02/03/2012 05:07 AM, Mihamina Rakotomandimby wrote: Searching the web I only found about creating a file /etc/sysconfig/network-scripts/ifcfg-br0, but did not find where to explicitely list what ports will be bridged. Where is it configured? For reference: As far as I know, bridged networking is only really documented for virtualization, but this link covers creation of a bridge and adding a single interface to it, and disabling iptables for bridges: http://docs.redhat.com/docs/en-US/Red_Hat_Enterprise_Linux/5/html/Virtualization/sect-Virtualization-Network_Configuration-Bridged_networking_with_libvirt.html You'd simply set up both eth2 and eth3 as eth0 is set up in that example. The options available in ifcfg files are documented in: /usr/share/doc/initscripts-*/sysconfig.txt ___ CentOS mailing list CentOS@centos.org http://lists.centos.org/mailman/listinfo/centos
Re: [CentOS] mysql won't start with service, but starts with mysqld_safe
On Sun, Feb 5, 2012 at 11:58 AM, Larry Martell larry.mart...@gmail.com wrote:
On Sun, Feb 5, 2012 at 10:31 AM, Tait Clarridge t...@taiter.com wrote:
On Sat, 2012-02-04 at 17:15 -0700, Larry Martell wrote:
Just installed mysql on centos 6.2. When I try to start it with service I
get:
#service mysqld start
MySQL Daemon failed to start.
Starting mysqld: [FAILED]
Nothing at all is written to the error log.
But if I start it with mysqld_safe it comes up and works fine.
Anyone know what's going on here?
Did it hang while trying to start? Or was it an immediate failure.
Immediate - the 'MySQL Daemon failed to start' message comes out right away.
I was curious as to exactle what 'service mysqld start' did (as
opposed to mysqld_safe, which works) so I traced it. Really didn't
glean anything useful from it - perhaps someone will see something
meaningful:
#strace service mysqld start
execve(/sbin/service, [service, mysqld, start], [/* 20 vars */]) = 0
brk(0) = 0x9873000
mmap2(NULL, 4096, PROT_READ|PROT_WRITE, MAP_PRIVATE|MAP_ANONYMOUS, -1,
0) = 0xb775e000
access(/etc/ld.so.preload, R_OK) = -1 ENOENT (No such file or
directory)
open(/etc/ld.so.cache, O_RDONLY) = 3
fstat64(3, {st_mode=S_IFREG|0644, st_size=92683, ...}) = 0
mmap2(NULL, 92683, PROT_READ, MAP_PRIVATE, 3, 0) = 0xb7747000
close(3) = 0
open(/lib/libtinfo.so.5, O_RDONLY) = 3
read(3,
\177ELF\1\1\1\0\0\0\0\0\0\0\0\0\3\0\3\0\1\0\0\0\260\3723\0064\0\0\0...,
512) = 512
fstat64(3, {st_mode=S_IFREG|0755, st_size=99636, ...}) = 0
mmap2(0x633a000, 101528, PROT_READ|PROT_EXEC,
MAP_PRIVATE|MAP_DENYWRITE, 3, 0) = 0x633a000
mmap2(0x635, 12288, PROT_READ|PROT_WRITE,
MAP_PRIVATE|MAP_FIXED|MAP_DENYWRITE, 3, 0x15) = 0x635
close(3) = 0
open(/lib/libdl.so.2, O_RDONLY) = 3
read(3,
\177ELF\1\1\1\0\0\0\0\0\0\0\0\0\3\0\3\0\1\0\0\0`\352\237\0004\0\0\0...,
512) = 512
fstat64(3, {st_mode=S_IFREG|0755, st_size=19784, ...}) = 0
mmap2(0x9fe000, 16500, PROT_READ|PROT_EXEC, MAP_PRIVATE|MAP_DENYWRITE,
3, 0) = 0x9fe000
mmap2(0xa01000, 8192, PROT_READ|PROT_WRITE,
MAP_PRIVATE|MAP_FIXED|MAP_DENYWRITE, 3, 0x2) = 0xa01000
close(3) = 0
open(/lib/libc.so.6, O_RDONLY) = 3
read(3,
\177ELF\1\1\1\3\0\0\0\0\0\0\0\0\3\0\3\0\1\0\0\0@\236\203\0004\0\0\0...,
512) = 512
fstat64(3, {st_mode=S_IFREG|0755, st_size=1876448, ...}) = 0
mmap2(0x823000, 1636744, PROT_READ|PROT_EXEC,
MAP_PRIVATE|MAP_DENYWRITE, 3, 0) = 0x823000
mprotect(0x9ac000, 4096, PROT_NONE) = 0
mmap2(0x9ad000, 12288, PROT_READ|PROT_WRITE,
MAP_PRIVATE|MAP_FIXED|MAP_DENYWRITE, 3, 0x189) = 0x9ad000
mmap2(0x9b, 10632, PROT_READ|PROT_WRITE,
MAP_PRIVATE|MAP_FIXED|MAP_ANONYMOUS, -1, 0) = 0x9b
close(3) = 0
mmap2(NULL, 4096, PROT_READ|PROT_WRITE, MAP_PRIVATE|MAP_ANONYMOUS, -1,
0) = 0xb7746000
mmap2(NULL, 4096, PROT_READ|PROT_WRITE, MAP_PRIVATE|MAP_ANONYMOUS, -1,
0) = 0xb7745000
set_thread_area({entry_number:-1 - 6, base_addr:0xb7746b30,
limit:1048575, seg_32bit:1, contents:0, read_exec_only:0,
limit_in_pages:1, seg_not_present:0, useable:1}) = 0
mprotect(0xa01000, 4096, PROT_READ) = 0
mprotect(0x9ad000, 8192, PROT_READ) = 0
mprotect(0x81b000, 4096, PROT_READ) = 0
munmap(0xb7747000, 92683) = 0
rt_sigprocmask(SIG_BLOCK, NULL, [], 8) = 0
open(/dev/tty, O_RDWR|O_NONBLOCK|O_LARGEFILE) = 3
close(3) = 0
brk(0) = 0x9873000
brk(0x9894000) = 0x9894000
open(/usr/lib/locale/locale-archive, O_RDONLY|O_LARGEFILE) = 3
fstat64(3, {st_mode=S_IFREG|0644, st_size=99158672, ...}) = 0
mmap2(NULL, 2097152, PROT_READ, MAP_PRIVATE, 3, 0) = 0xb7545000
close(3) = 0
getuid32() = 0
getgid32() = 0
geteuid32() = 0
getegid32() = 0
rt_sigprocmask(SIG_BLOCK, NULL, [], 8) = 0
time(NULL) = 1328468051
open(/proc/meminfo, O_RDONLY) = 3
fstat64(3, {st_mode=S_IFREG|0444, st_size=0, ...}) = 0
mmap2(NULL, 4096, PROT_READ|PROT_WRITE, MAP_PRIVATE|MAP_ANONYMOUS, -1,
0) = 0xb775d000
read(3, MemTotal: 3741948 kB\nMemF..., 1024) = 1024
close(3) = 0
munmap(0xb775d000, 4096) = 0
rt_sigaction(SIGCHLD, {SIG_DFL, [], 0}, {SIG_DFL, [], 0}, 8) = 0
rt_sigaction(SIGCHLD, {SIG_DFL, [], 0}, {SIG_DFL, [], 0}, 8) = 0
rt_sigaction(SIGINT, {SIG_DFL, [], 0}, {SIG_DFL, [], 0}, 8) = 0
rt_sigaction(SIGINT, {SIG_DFL, [], 0}, {SIG_DFL, [], 0}, 8) = 0
rt_sigaction(SIGQUIT, {SIG_DFL, [], 0}, {SIG_DFL, [], 0}, 8) = 0
rt_sigaction(SIGQUIT, {SIG_DFL, [], 0}, {SIG_DFL, [], 0}, 8) = 0
rt_sigprocmask(SIG_BLOCK, NULL, [], 8) = 0
Re: [CentOS] mysql won't start with service, but starts with mysqld_safe
On 02/05/12 1:22 PM, Larry Martell wrote: clone(child_stack=0, flags=CLONE_CHILD_CLEARTID|CLONE_CHILD_SETTID|SIGCHLD, child_tidptr=0xb7746b98) = 17017 wild guess says, its forking itself, and THAT process invokes /etc/init.d/mysqld -- john r pierceN 37, W 122 santa cruz ca mid-left coast ___ CentOS mailing list CentOS@centos.org http://lists.centos.org/mailman/listinfo/centos
Re: [CentOS] distributed storage/home-made cloud recommendations
On Feb 5, 2012, at 10:32 AM, Phil Schaffner philip.r.schaff...@nasa.gov wrote: Boris Epstein wrote on 02/04/2012 11:57 AM: What is RAID0+1? Nested RAID. Paraphrasing http://en.wikipedia.org/wiki/RAID : For a RAID 0+1, drives are first combined into multiple level 0 RAIDs that are themselves treated as single drives to be combined into a single RAID 1. Probably the worse setup, a failure on both sides of a mirror means total loss and with the # of disks on each side of this setup the chance of this is much greater, recovery from a failure is a lot longer cause the whole stripe needs to re-mirror. While performance of reads is equal to 1+0 the writes are equal to a single mirror cause both sides need to complete before the next operation can run or only one write operation on the array at a time. Much better RAID level is 1+0 which is a series of mirrors striped together. While a failure on both sides of any one mirror is total for the array there is only 1 disk on either side so the odds are less, recovery from failure is faster as well cause only one disk needs to be re-mirrored. Performance of reads and writes are equal because each mirror can perform writes independant of the others, or # of write operations equal to the number of mirrors. -Ross ___ CentOS mailing list CentOS@centos.org http://lists.centos.org/mailman/listinfo/centos
Re: [CentOS] distributed storage/home-made cloud recommendations
On Sun, Feb 5, 2012 at 5:31 PM, Ross Walker rswwal...@gmail.com wrote: On Feb 5, 2012, at 10:32 AM, Phil Schaffner philip.r.schaff...@nasa.gov wrote: Boris Epstein wrote on 02/04/2012 11:57 AM: What is RAID0+1? Nested RAID. Paraphrasing http://en.wikipedia.org/wiki/RAID : For a RAID 0+1, drives are first combined into multiple level 0 RAIDs that are themselves treated as single drives to be combined into a single RAID 1. Probably the worse setup, a failure on both sides of a mirror means total loss and with the # of disks on each side of this setup the chance of this is much greater, recovery from a failure is a lot longer cause the whole stripe needs to re-mirror. While performance of reads is equal to 1+0 the writes are equal to a single mirror cause both sides need to complete before the next operation can run or only one write operation on the array at a time. Much better RAID level is 1+0 which is a series of mirrors striped together. While a failure on both sides of any one mirror is total for the array there is only 1 disk on either side so the odds are less, recovery from failure is faster as well cause only one disk needs to be re-mirrored. Performance of reads and writes are equal because each mirror can perform writes independant of the others, or # of write operations equal to the number of mirrors. -Ross ___ CentOS mailing list CentOS@centos.org http://lists.centos.org/mailman/listinfo/centos Ross, What you are saying seems to make sense actually. I wonder how much a RAID6 with a few spares would make sense. If we are talking a large number of disks then RAID 6 + 2 spares means overpaying only for 5 disks. Not a lot if the total number of them is, say, 20. Boris. ___ CentOS mailing list CentOS@centos.org http://lists.centos.org/mailman/listinfo/centos
Re: [CentOS] distributed storage/home-made cloud recommendations
On 02/05/12 2:42 PM, Boris Epstein wrote: What you are saying seems to make sense actually. I wonder how much a RAID6 with a few spares would make sense. If we are talking a large number of disks then RAID 6 + 2 spares means overpaying only for 5 disks. Not a lot if the total number of them is, say, 20. except, you don't want more than about 12 disks max in a single raid5/6 group, or the performance penalties become enormous and the rebuild times become astronomical. -- john r pierceN 37, W 122 santa cruz ca mid-left coast ___ CentOS mailing list CentOS@centos.org http://lists.centos.org/mailman/listinfo/centos
Re: [CentOS] distributed storage/home-made cloud recommendations
On Feb 5, 2012, at 5:42 PM, Boris Epstein borepst...@gmail.com wrote: What you are saying seems to make sense actually. I wonder how much a RAID6 with a few spares would make sense. If we are talking a large number of disks then RAID 6 + 2 spares means overpaying only for 5 disks. Not a lot if the total number of them is, say, 20. Don't approach it as purely a cost analysis, but what you require for your application. If you have a write-mostly transactional application then RAID10 makes sense, if you have 50/50 app then maybe a RAID50 out of several small RAID5s, if you have a read mostly or long-term archival storage then a RAID6. I wouldn't create an array out of more then 12 disks unless it was a RAID10 cause rebuild times would put the array in jeopardy of a cascading failure. You could create a RAID50 out of 3 6 disk RAID5s with 2 hot spares. That's 15 disk usable space with 3 disks of parity and 2 disk spares. That would give decent performance with ability to handle 3 disk failures (spread across different RAID5s). When setting it up setup every third disk as part of a RAID5 just cause I have seen double failures and for some reason they were side-by-side for me. It might be easier to do the striping in software cause that's a zero over-head operation and it makes the hardware RAID easier to setup, maintain and can make rebuilds less painful depending on the controller. -Ross ___ CentOS mailing list CentOS@centos.org http://lists.centos.org/mailman/listinfo/centos
Re: [CentOS] distributed storage/home-made cloud recommendations
On 02/05/12 3:24 PM, Ross Walker wrote: It might be easier to do the striping in software cause that's a zero over-head operation and it makes the hardware RAID easier to setup, maintain and can make rebuilds less painful depending on the controller. I just tried a bunch of combinations on a 3 x 11 raid60 configuration plus 3 global hotspares, and decided that letting the controller (LSI 9260-8i MegaSAS2) do it was easier all the way around. of course, with other controllerrs, your mileage may vary. and yes, megacli64 is an ugly tool to tame. with 3TB SAS drives, single drive failures rebuild in 12 hours, double failures in 18 hours. (failures forced by disabling drives via megacli) -- john r pierceN 37, W 122 santa cruz ca mid-left coast ___ CentOS mailing list CentOS@centos.org http://lists.centos.org/mailman/listinfo/centos
Re: [CentOS] distributed storage/home-made cloud recommendations
On 02/06/2012 12:33 AM, John R Pierce wrote: On 02/05/12 3:24 PM, Ross Walker wrote: It might be easier to do the striping in software cause that's a zero over-head operation and it makes the hardware RAID easier to setup, maintain and can make rebuilds less painful depending on the controller. I just tried a bunch of combinations on a 3 x 11 raid60 configuration plus 3 global hotspares, and decided that letting the controller (LSI 9260-8i MegaSAS2) do it was easier all the way around. of course, with other controllerrs, your mileage may vary. and yes, megacli64 is an ugly tool to tame. with 3TB SAS drives, single drive failures rebuild in 12 hours, double failures in 18 hours. (failures forced by disabling drives via megacli) What about Software RAID 10 (far)? It gives 2 x read speed and 1 x write speed (speed of single HDD). -- Ljubomir Ljubojevic (Love is in the Air) PL Computers Serbia, Europe Google is the Mother, Google is the Father, and traceroute is your trusty Spiderman... StarOS, Mikrotik and CentOS/RHEL/Linux consultant ___ CentOS mailing list CentOS@centos.org http://lists.centos.org/mailman/listinfo/centos
Re: [CentOS] distributed storage/home-made cloud recommendations
On 02/05/12 3:49 PM, Ljubomir Ljubojevic wrote: What about Software RAID 10 (far)? It gives 2 x read speed and 1 x write speed (speed of single HDD). we use raid10 for all our database servers. often as many as 20 disks in a single raid set. -- john r pierceN 37, W 122 santa cruz ca mid-left coast ___ CentOS mailing list CentOS@centos.org http://lists.centos.org/mailman/listinfo/centos
Re: [CentOS] configure network bridge listing bridged intefaces
On 02/04/2012 07:53 AM, Robert Spangler wrote: snip DEVICE=eth# ONBOOT=yes BRIDGE=br# /snip Thank you so much, Robert. That is the thing I wanted to do. For the record, in Debian world, it's auto br0 iface br0 inet static address 192.168.0.10 network 192.168.0.0 netmask 255.255.255.0 broadcast 192.168.0.255 gateway 192.168.0.1 bridge_ports eth0 # - here you list bridged ports I was a bit lost, I looked for that definition in the bridge conf file instead of the interface one. Thank you again. -- RMA. ___ CentOS mailing list CentOS@centos.org http://lists.centos.org/mailman/listinfo/centos
Re: [CentOS] network intermitent, not sure if virtualization issue
--- snip centos 6 host, centos 6 virtual machine. Network connection from outside server disappears in regards to the virtual server. snip --- Tested the heck out of it. Further testing shows the network unreachable, even if network restarted in host. A simple ping from the virtual machine going out allows full traffic both ways. Intermittent time out, it may last 5 minutes, it may last an hour, but it will disappear. I found a small config sample on an old website in the middle of nowhere. It had an addition to the /etc/sysconfig/network file of the host. it added GATEWAY=br0 I did this and restarted the network service and I believe without me doing anything, this appeared in the virtual machine message logs, something that had never appeared before. kernel: Bridge firewalling registered so hoping that is it...not sure if I would need to do that on the virtual machine or not. I have been days at this. Literally rewrote every single ifcfg and conf file I could find. Tried hundreds of permutations. Nothing has worked. If this does not work I am willing to pay someone to end my week long battle with the virtual machine network being unreachable no matter what I do. But only if you actually know this stuff and actually have experience with the virtual machine bridging..and hopefully have seen this type of issue... banging head on wall repeat rinse repeat ___ CentOS mailing list CentOS@centos.org http://lists.centos.org/mailman/listinfo/centos
