Surprised no one here has mentioned mfsBSD. It's an unofficial FreeBSD answer to this problem. Works very well for some maintenance tasks, like ensuring a new install's disks are clear of partitions/zpools. I have even booted it's ISO via IPMI over the internet with OpenVPN.
Ramroot – Run Arch Linux Entirely from RAM (2017)
41–50 of 83 posts
Re: Ramroot – Run Arch Linux Entirely from RAM (2017)
#42In college, I would use computer lab computers as a proxy for my... experiments. I would just load up a small Linux distro from a CD into ram. That way, I could just reboot the computer when done, and it would reboot into Windows.
Re: Ramroot – Run Arch Linux Entirely from RAM (2017)
#43Many OS out there take advantage of RAM Disks. Alpine Linux for instance allows you to boot your root device on ram as a default. SmartOS runs a boot image completely on RAM, and keeps your storage free for a few configs and VMS. Virtually all network booted computers run their OSs from RAM. If you have never pxe booted a machine, it is a beautiful experience once you overcome a few challenges: easy upgrades and roll…
Sadly PXE boot of a modern Linux OS is easier said than done. Gone are the days of just handing out the kernel over tftp and providing a NFS root. SystemD gets super cranky and you can't even boot the thing without setting some undocumented flags.
Re: Ramroot – Run Arch Linux Entirely from RAM (2017)
#44Many OS out there take advantage of RAM Disks. Alpine Linux for instance allows you to boot your root device on ram as a default. SmartOS runs a boot image completely on RAM, and keeps your storage free for a few configs and VMS. Virtually all network booted computers run their OSs from RAM. If you have never pxe booted a machine, it is a beautiful experience once you overcome a few challenges: easy upgrades and roll…
Sadly PXE boot of a modern Linux OS is easier said than done. Gone are the days of just handing out the kernel over tftp and providing a NFS root. SystemD gets super cranky and you can't even boot the thing without setting some undocumented flags.
How did the systemd cabal manage to mess that up? I ditched that thing a while ago for good reasons, so I don't keep track anymore.
Re: Ramroot – Run Arch Linux Entirely from RAM (2017)
#45I'm on mobile so I'll keep this short but I found this[0] a long time ago and it still seems to work. It uses strace, mmap, and mlock to load any program you want and it's libraries, etc. into RAM but only those programs so if you're short on memory, no problem. During the setup, you can even mouse around in the program and preload anything involved in that. Back in the day I used it on really slow stuff like OpenOffice, Firefox, GIMP, etc. and it sped the opening of those programs significantly.
The great thing, again, is you set it to preload only the specific things you need into RAM and nothing you don't. And, once done, it's pretty much set and forget.
[0]https://forums.gentoo.org/viewtopic-t-622085-start-0.html
Re: Ramroot – Run Arch Linux Entirely from RAM (2017)
#46Once upon a time I did this using Mac OS 6 on a PowerBook 100. The 100 had pseudostatic RAM so the RAM disk would persist between shutdowns. Using OS6 left enough space on the disk to also run an old-for-the-time version of Word, a perfect silent student writing machine.
Some info about it here:
Re: Ramroot – Run Arch Linux Entirely from RAM (2017)
#47This is neat, but nothing new. I remember using this builtin feature on live distros like Slax and DSL over a decade ago. It was fun to see old computers run (comparably) blazingly fast.
The Amiga was able to create a "Recoverable RAM Disk" that survived reboots, back in the early 80s: https://grimore.org/amiga/rad
Re: Ramroot – Run Arch Linux Entirely from RAM (2017)
#48I wonder whether this achieves anything performance-wise that just cat'ing every file to /dev/null to warm up the buffer cache wouldn't achieve. In theory, the kernel uses a buffer cache that will hold on to disk pages until they're invalidated by writes. It'll evict the cache if there's memory pressure. But this setup will presumably just crash if there's memory pressure, so that doesn't seem like a win for the RAM…
One of the big advantages is that you do not need to install file systems on your storage for single purpose servers, which allows your application to run on top of the raw block devices. Databases and similar run much better in this configuration (assuming they support raw block devices), especially if you are running on top of a hypervisor.
Do you know of or could list which databases support raw block devices?
Re: Ramroot – Run Arch Linux Entirely from RAM (2017)
#49Many OS out there take advantage of RAM Disks. Alpine Linux for instance allows you to boot your root device on ram as a default. SmartOS runs a boot image completely on RAM, and keeps your storage free for a few configs and VMS. Virtually all network booted computers run their OSs from RAM. If you have never pxe booted a machine, it is a beautiful experience once you overcome a few challenges: easy upgrades and roll…
Sadly PXE boot of a modern Linux OS is easier said than done. Gone are the days of just handing out the kernel over tftp and providing a NFS root. SystemD gets super cranky and you can't even boot the thing without setting some undocumented flags.
What? I just did this today with Ubuntu 18, using dnsmasq and a nfsroot based on a virt-builder image. It runs fine..
Re: Ramroot – Run Arch Linux Entirely from RAM (2017)
#50Earlier quoted context omitted.
Sadly PXE boot of a modern Linux OS is easier said than done. Gone are the days of just handing out the kernel over tftp and providing a NFS root. SystemD gets super cranky and you can't even boot the thing without setting some undocumented flags.
How did the systemd cabal manage to mess that up? I ditched that thing a while ago for good reasons, so I don't keep track anymore.
I'm not entirely sure of everything, but problems with UUIDs (which we expected), and some dbus signals not being generated when run over a NFS mounted root causing the boot to hang. We hacked some timeouts to get around the problem but never figured out exactly where the signals were supposed to be generated from.
A hint if you're doing this on Linux. We PXEBoot an iPXE loader to boot the machines. Doesn't work properly on UEFI unfortunately, gotta use BIOS boot.
If it helps, I have notes on how to set that up:
Go to http://rom-o-matic.net and choose gPXE git. Click on the "Customize" button to expand all of the options.
Choose: 1. PXE bootstrap loader image [Unload PXE stack] (.pxe)
2. all-drivers
3. PCI VENDOR CODE: [blank] PCI DEVICE CODE: [blank]
X CONSOLE_PCBIOS
_ CONSOLE_SERIAL
BANNER_TIMEOUT [20]
_ NET_PROTO_IPV6
(Serial Port Options are irrelevant)
X DOWNLOAD_PROTO_TFTP
X DOWNLOAD_PROTO_HTTP
_ DOWNLOAD_PROTO_HTTPS
_ DOWNLOAD_PROTO_FTP
_ SANBOOT_PROTO_ISCSI
_ SANBOOT_PROTO_AOE
X DNS_RESOLVER
X IMAGE_ELF
X IMAGE_NBI
X IMAGE_MULTIBOOT
X IMAGE_PXE
X IMAGE_SCRIPT
X IMAGE_BZIMAGE
X IMAGE_COMBOOT
X AUTOBOOT_CMD
X NVO_CMD
X CONFIG_CMD
X IFMGMT_CMD
X IWMGMT_CMD
X ROUTE_CMD
X IMAGE_CMD
X DHCP_CMD
_ SANBOOT_CMD
X LOGIN_CMD
_ TIME_CMD
_ DIGEST_CMD
X PXE_CMD
_ IPV6_CMD
_ CRYPTO_80211_WEP
_ CRYPTO_80211_WPA
_ CRYPTO_80211_WPA2
Embedded Script:
-----------------------------------------------------------------------------
#!gpxe
dhcp any
initrd /initrd.img" rel="nofollow">http:///initrd.img
kernel /pxelinux.0" rel="nofollow">http:///pxelinux.0
imgargs pxelinux.0 root=/dev/nfs rw boot=nfs nfsroot=:/netroot root ip=dhcp nfsrootdebug
boot pxelinux.0
-----------------------------------------------------------------------------