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Diskless Linux boot using ZFS, iSCSI and PXE

aniket.foo

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Re: Diskless Linux boot using ZFS, iSCSI and PXE

#101

Post by awesomeusername »

nicman23 wrote: post #81
creshal wrote: post #71

Earlier quoted context omitted.

~90% of the failure modes grub can fix don't exist without grub. I can't remember any time when its needless complexity was actually a net benefit compared to literally any of its alternatives (and between gummiboot/syslinux/efilinux/isolinux/systemd-boot/efistub I've used a lot of them).

i like grub, but i also remember pre-0.98 grub

i love HN but also starting to think it's time for us oldies to have our own one: cost of entry, having a distant memory of booting linux from a floppy

Re: Diskless Linux boot using ZFS, iSCSI and PXE

#102

Post by nicman23 »

awesomeusername wrote: post #101
nicman23 wrote: post #81

Earlier quoted context omitted.

i like grub, but i also remember pre-0.98 grub

i love HN but also starting to think it's time for us oldies to have our own one: cost of entry, having a distant memory of booting linux from a floppy

i have the memory of bios being so shit that i had to boot grub from a floppy to boot from a cd

Re: Diskless Linux boot using ZFS, iSCSI and PXE

#103

Post by lproven »

p_l wrote: post #73
lproven wrote: post #64

Earlier quoted context omitted.

> rEFInd is _so_ much simpler TBH I've only used it for Hackintoshes and BSDs. I don't know why you'd want it. But I am finding this hard to post on account of this big hairy grey thing with a long prehensile nose that's in the way... They only work on UEFI. I don't like UEFI. I have kit in near-daily use that doesn't have UEFI at all. GRUB works on BIOS, UEFI, x86, Arm, whatever. It boots Linux, all the BSDs, Haiku,…

You haven't upgraded any x86 compatible beyond 2005? /s

/s notwithstanding... no.

I run a bunch of decade-old HP Microservers. All BIOS-only.

My personal laptops are old Thinkpads, from before the keyboards went crappy & Lenovo took away the expansion options. So they're all about 15, ?20 generation at the newest, but they are all maxed-out and go like stink. BIOS boot mode optional.

My default hypervisor is VirtualBox, because it runs the same on Linux, Windows and Mac. Defaults to BIOS boot.

This is not like some ancient history. All run current OSes and distros.

Re: Diskless Linux boot using ZFS, iSCSI and PXE

#104

Post by p_l »

lproven wrote: post #103
p_l wrote: post #73

Earlier quoted context omitted.

You haven't upgraded any x86 compatible beyond 2005? /s

/s notwithstanding... no. I run a bunch of decade-old HP Microservers. All BIOS-only. My personal laptops are old Thinkpads, from before the keyboards went crappy & Lenovo took away the expansion options. So they're all about 15, ?20 generation at the newest, but they are all maxed-out and go like stink. BIOS boot mode optional. My default hypervisor is VirtualBox, because it runs the same on Linux, Windows and Mac.…

Thinkpads were all UEFI since T410 (and related other models), not to mention a lot of non-thinkpad machines since ~2005 were UEFI Type 1 (i.e. "always boot to BIOS emulation mode, but everything underneath is UEFI").

Thus the /s :-)

Re: Diskless Linux boot using ZFS, iSCSI and PXE

#105

Post by hnarn »

nikisweeting wrote: post #91
cwillu wrote: post #44

Friends don't let friends use grub. rEFInd is _so_ much simpler: one efi entry, one text config file in the efi partition, nothing that needs to change when the kernel updates, and no massive pile of templating and moving parts to mysteriously break dumping you at an impenetrable grub “rescue” shell.

Or even better: https://zfsbootmenu.org/

I use zfsbootmenu and I love it.

Re: Diskless Linux boot using ZFS, iSCSI and PXE

#106

Post by cwillu »

awesomeusername wrote: post #101
nicman23 wrote: post #81

Earlier quoted context omitted.

i like grub, but i also remember pre-0.98 grub

i love HN but also starting to think it's time for us oldies to have our own one: cost of entry, having a distant memory of booting linux from a floppy

My first linux system was a linux-on-a-floppy router that I ran on a spare 386 with two cards to provide NAT for my house, back in the days when internet providers tried to ban people for doing that.

Re: Diskless Linux boot using ZFS, iSCSI and PXE

#108

Post by olavgg »

RulerOf wrote: post #99
olavgg wrote: post #35

Earlier quoted context omitted.

Using a proper NIC (Chelsio) with their iSCSI accelerator will boost your iSCSI performance significantly. Another alternative is Mellanox with RDMA. You need CX4+ for optimal performance over TCP/IP, while the cheap CX3 is excellent with IPoIB. If you have a lot of packet drops and retransmissions, another option for boosting iSCSI performance is getting a network switch with a lot of memory for packet buffering. Th…

> Another alternative is Mellanox with RDMA. You need CX4+ for optimal performance over TCP/IP, while the cheap CX3 is excellent with IPoIB. Do these benefit the iSCSI target end of the equation too, or just the initiator? And do they work like an HBA, where you configure the card in a firmware setup menu, or does it just transparently accelerate the software initiator on Windows/Linux?

It is a bit different, Mellanox with iSCSI/iSER over IB/RoCE is much less complex than iSCSI over TCP. RoCE runs over UDP, but requires switches with PFC, and ECN. Chelsio plays nice with any switch. Mellanox has much better offloading of NVMe-oF, where the network card can directly communicate with the NVMe device over pci-express so it can completely bypass system ram and host cpu. In fact, Linux will know nothing about the transfers to and from the NVMe device.

To get accelerated iSCSI, you need to install Chelsio or Mellanox drivers. While both work out of the box with the inbox drivers, they have special drivers that you have to download and install to unlock the extra performance. I think Chelsio has everything included in FreeBSD, so there the inbox drivers already come with top performance unlocked.

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