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I'm booting my Raspberry Pi 4 from a USB SSD

jeffgeerling.com

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Re: I'm booting my Raspberry Pi 4 from a USB SSD

#3

Post by ajflores1604 »

Does anyone know if its theoretically possible to run a cluster of Pi's off of the same external ssd at the same time? I'd like for say 4 Pi's to get a speed boost of not running off microSD, but I also don't want to shell out for 4 separate hard drives.

I've looked in the past and have only found links to partitioning the drive so that it could be used when moving from one pi to another. But nothing about using it concurrently.

I'm not even sure what this would look like physically. Like if a hub exists that could pass traffic to a single drive connected on the other side. Or how the drive would internally separate the writes. But im curious if something like this has been done before. Or why it couldn't be done

Re: I'm booting my Raspberry Pi 4 from a USB SSD

#4

Post by zamadatix »

ajflores1604 wrote: post #3

Does anyone know if its theoretically possible to run a cluster of Pi's off of the same external ssd at the same time? I'd like for say 4 Pi's to get a speed boost of not running off microSD, but I also don't want to shell out for 4 separate hard drives. I've looked in the past and have only found links to partitioning the drive so that it could be used when moving from one pi to another. But nothing about using it c…

Networked storage but that won't be as fast as native drives.

Re: I'm booting my Raspberry Pi 4 from a USB SSD

#6

Post by schlopper »

ajflores1604 wrote: post #3

Does anyone know if its theoretically possible to run a cluster of Pi's off of the same external ssd at the same time? I'd like for say 4 Pi's to get a speed boost of not running off microSD, but I also don't want to shell out for 4 separate hard drives. I've looked in the past and have only found links to partitioning the drive so that it could be used when moving from one pi to another. But nothing about using it c…

PXE Boot w/ NFS root - you won't get the bandwidth (about 112MB/s over gigabit Ethernet), but you'll definitely see the response time improvements (IOPS + latency).

Re: I'm booting my Raspberry Pi 4 from a USB SSD

#7

Post by geerlingguy »

schlopper wrote: post #6
ajflores1604 wrote: post #3

Does anyone know if its theoretically possible to run a cluster of Pi's off of the same external ssd at the same time? I'd like for say 4 Pi's to get a speed boost of not running off microSD, but I also don't want to shell out for 4 separate hard drives. I've looked in the past and have only found links to partitioning the drive so that it could be used when moving from one pi to another. But nothing about using it c…

PXE Boot w/ NFS root - you won't get the bandwidth (about 112MB/s over gigabit Ethernet), but you'll definitely see the response time improvements (IOPS + latency).

This. I intend to do some more testing with my current cluster to see how much improvement I can get with one Pi 4 serving the traffic (vs each Pi running from its microSD card). And ideally seeing if a faster machine with faster storage could do even better.

Re: I'm booting my Raspberry Pi 4 from a USB SSD

#9

Post by ajflores1604 »

geerlingguy wrote: post #7
schlopper wrote: post #6

Earlier quoted context omitted.

PXE Boot w/ NFS root - you won't get the bandwidth (about 112MB/s over gigabit Ethernet), but you'll definitely see the response time improvements (IOPS + latency).

This. I intend to do some more testing with my current cluster to see how much improvement I can get with one Pi 4 serving the traffic (vs each Pi running from its microSD card). And ideally seeing if a faster machine with faster storage could do even better.

If you end up doing this you should definitely make a post about it. I'm sure I'm not the only one incredibly curious on the real world performance and tradeoffs

Re: I'm booting my Raspberry Pi 4 from a USB SSD

#10

Post by lmilcin »

chopin wrote: post #8
yummypaint wrote: post #2

Excellent. The biggest obstacle ive had to using Pis for practical things is that the memory cards eventually go bad. Looking forward to seeing this in the main release.

Putting /var/log/ somewhere else mitigates this.

Couple more things to remember:

- don't use swap

- make sure you have noatime on all your filesystems

- identify other folders with frequently changing data (/tmp, $HOME/tmp, etc.) and also make sure you keep them in memory

- you can use NFS for many of these things if that is possible

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