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CentOS with low RAM (poll)
I'd like to do some "market research" on this specific topic.
Are you running CentOS on a machine with 128MB of memory or less?
If so, do you have SELinux enabled in enforcing mode? (Check with: sestatus | grep "Current mode").
I'm interested in CentOS users with or without SELinux. Please, vote even if you are not running low-RAM machines.
Running CentOS with low RAM
- Are you running CentOS on 128MB or less of RAM?74 votes
- No74.32%
- Yes, without SELinux22.97%
- Yes, with SELinux2.70%
Comments
Since you're talking about SELinux, I assume you're referring to a KVM (full virtualization) VPS.
If you ask me, a 128MB KVM / Full Virt. VPS is just a no-go, with or without SELinux enabled. Basically all memory will go directly to the OS/kernel, with nothing left for other services.
Yeah, I am fully aware of that.
But as you can see, there are still some users who really want CentOS in those small VMs. I'm interested in how many.
Forget it.
Honestly, Debian is the way to go in my opinion with low-RAM VPS servers.
For production systems, CentOS is definitely an option but using it with 128MB of RAM on a KVM VPS will not work well.
I am not thinking about doing it. I don't even use CentOS a lot.
For context, this thread was opened in relation to:
http://forum.lowendspirit.com/viewtopic.php?pid=14349#p14349
The CentOS 7 installer (ISO) doesn't even run on 256MB.
In my opinion a KVM VPS with 128MB ram is just worthless these days - software really needs more memory to function properly.
A few of those 128MB ram KVM will most likely knock your VPS node down due all the swap I/O that is guaranteed to be expected.
If you really want 128MB ram, go with OpenVZ and forget full virtualization with selinux. This way you have at least 128MB memory to play with :-) Plenty for a little DNS box.
So what do you say about my Debian 128MB KVM central logging and monitoring server that has been running flawlessly for 2 years?
What is CentOS?
thx debian
I am running both Openvz and KVM mainly on CentOS 6 and 7. None of the VPS server have any problem.
The lowest Openvz VPS was bought 2 days ago from Sentris.net mainly for testing purpose.
https://www.lowendtalk.com/discussion/83364/cheap-vps-64mb-5gb-1ipv4-250gb-at-1-99-a-year#latest
Surprisingly, it work flawlessly with just a penny cost at $1.99 a year.
For KVM, I bought from onrahost.com and performance are solid and uptime are great. I still have room to fine-tuning the Memory usage. The only downtime was due to migration process about 10 days ago.
KVM VPS at 128MB
cat /proc/meminfo
free -m
total used free shared buffers cached Mem: 115 112 2 37 2 54 -/+ buffers/cache: 55 59 Swap: 126 6 120wget freevps.us/downloads/bench.sh -O - -o /dev/null|bash
top
top - 02:34:01 up 10 days, 3:39, 1 user, load average: 0.00, 0.01, 0.05 Tasks: 66 total, 1 running, 65 sleeping, 0 stopped, 0 zombie Cpu(s): 0.1%us, 0.0%sy, 0.0%ni, 99.7%id, 0.1%wa, 0.0%hi, 0.0%si, 0.0%st Mem: 117852k total, 115440k used, 2412k free, 2796k buffers Swap: 130044k total, 7164k used, 122880k free, 55632k cached PID USER PR NI VIRT RES SHR S %CPU %MEM TIME+ COMMAND 1 root 20 0 2900 220 104 S 0.0 0.2 0:00.65 init 2 root 20 0 0 0 0 S 0.0 0.0 0:00.00 kthreadd 3 root RT 0 0 0 0 S 0.0 0.0 0:00.00 migration/0 4 root 20 0 0 0 0 S 0.0 0.0 0:03.71 ksoftirqd/0 5 root RT 0 0 0 0 S 0.0 0.0 0:00.00 stopper/0 6 root RT 0 0 0 0 S 0.0 0.0 0:04.61 watchdog/0 7 root 20 0 0 0 0 S 0.0 0.0 0:21.74 events/0 8 root 20 0 0 0 0 S 0.0 0.0 0:00.00 events/0 9 root 20 0 0 0 0 S 0.0 0.0 0:00.00 events_long/0 10 root 20 0 0 0 0 S 0.0 0.0 0:00.00 events_power_ef 11 root 20 0 0 0 0 S 0.0 0.0 0:00.00 cgroup 12 root 20 0 0 0 0 S 0.0 0.0 0:00.00 khelper 13 root 20 0 0 0 0 S 0.0 0.0 0:00.00 netns 14 root 20 0 0 0 0 S 0.0 0.0 0:00.00 async/mgr 15 root 20 0 0 0 0 S 0.0 0.0 0:00.00 pm 16 root 20 0 0 0 0 S 0.0 0.0 0:02.58 sync_supers 17 root 20 0 0 0 0 S 0.0 0.0 0:02.83 bdi-default 18 root 20 0 0 0 0 S 0.0 0.0 0:00.00 kintegrityd/0 19 root 20 0 0 0 0 S 0.0 0.0 0:01.27 kblockd/0 20 root 20 0 0 0 0 S 0.0 0.0 0:00.00 ata_aux 21 root 20 0 0 0 0 S 0.0 0.0 0:00.00 ata_sff/0 22 root 20 0 0 0 0 S 0.0 0.0 0:00.00 ksuspend_usbd 23 root 20 0 0 0 0 S 0.0 0.0 0:00.00 khubd 24 root 20 0 0 0 0 S 0.0 0.0 0:00.00 kseriod 25 root 20 0 0 0 0 S 0.0 0.0 0:00.00 md/0 26 root 20 0 0 0 0 S 0.0 0.0 0:00.00 md_misc/0 27 root 20 0 0 0 0 S 0.0 0.0 0:00.00 linkwatch 28 root 20 0 0 0 0 S 0.0 0.0 0:00.14 khungtaskd 29 root 20 0 0 0 0 D 0.0 0.0 0:06.97 kswapd0 30 root 25 5 0 0 0 S 0.0 0.0 0:00.00 ksmd 31 root 20 0 0 0 0 S 0.0 0.0 0:00.00 aio/0 32 root 20 0 0 0 0 S 0.0 0.0 0:00.00 crypto/0 39 root 20 0 0 0 0 S 0.0 0.0 0:00.00 kthrotld/0 41 root 20 0 0 0 0 S 0.0 0.0 0:00.00 kpsmoused 42 root 20 0 0 0 0 S 0.0 0.0 0:00.00 usbhid_resumer 43 root 20 0 0 0 0 S 0.0 0.0 0:00.00 deferwq 150 root 20 0 0 0 0 S 0.0 0.0 0:00.00 scsi_eh_0 151 root 20 0 0 0 0 S 0.0 0.0 0:00.00 scsi_eh_1 187 root 20 0 0 0 0 S 0.0 0.0 0:02.58 jbd2/sda1-8 188 root 20 0 0 0 0 S 0.0 0.0 0:00.00 ext4-dio-unwrit 264 root 16 -4 2540 8 4 S 0.0 0.0 0:00.05 udevd 342 root 20 0 87732 1968 44 S 0.0 1.7 0:00.00 nginx 344 www 20 0 165m 23m 5624 S 0.0 20.3 1:08.09 nginx 355 root 20 0 116m 3448 312 S 0.0 2.9 0:09.63 php-fpm 449 root 20 0 0 0 0 S 0.0 0.0 0:00.00 hd-audio0 459 root 20 0 0 0 0 S 0.0 0.0 0:00.00 vballoon 488 root 18 -2 2536 8 4 S 0.0 0.0 0:00.00 udevd@b6688
The fact that you can boot the OS with this low amount of RAM doesn't immediately mean that it will be usable.
From the looks of your pasted output I see that this box is just running a web server which isn't even serving requests at that time. Hardly an example of real usage.
Are you the one who voted for SELinux? May I ask how you manage it? Since
semanagewill not work, I can only think ofaudit2allowor something like that, which has some serious limitations.Anyway the situation is clear to me now: not many users install CentOS with a very low amount of RAM, but those who do, very rarely will try to use SELinux. Thanks to everyone for participating.
@Nyr
This KVM VPS have been deployed into production mode and have been use by several people but not much traffic yet.
No, I vote for Without SELinux. I don't use it even with the Higher RAM. I don't like it as it have created a lot more issue to me when the SELinux is enabled.
To me, CentOS is perfect for production environment as it doesn't cause any issue.
Your opinion is quite wrong.
There are some things that should be pointed out if they haven't already. If you run it on OpenVZ you are not running any kernelspace which saves anywhere from 15 to 50MB of RAM.
64bit uses more memory than 32bit. In some cases significantly more such as when you are running a LAMP stack.
We are talking about SELinux here so OpenVZ is not an option.