Saw a trick today, wondering if anybody else had done/tried this? Assume you have a 1U rackmount with 4 front-accessed drive bays, and you want all four bays for a 4-disk RAID5 storage.
The idea is to use an internal USB adapter and a couple of bigger USB thumb drives to install to, RAID 1 style, freeing up all your external drive bays. At first, I didn't think that a thumb drive would hold enough for the O/S, but in actual production use for a file server with 14 TB of redundant storage, the OS actually uses less than 6 GB!
Here's the internal USB adapter specifically mentioned: http://www.amazon.com/gp/product/B007PODI1W
I'd be concerned about getting a higher quality drive than the $10 givaways at Staples; Anybody here ever tried this?
On 2013-11-08, Lists lists@benjamindsmith.com wrote:
The idea is to use an internal USB adapter and a couple of bigger USB thumb drives to install to, RAID 1 style, freeing up all your external drive bays. At first, I didn't think that a thumb drive would hold enough for the O/S, but in actual production use for a file server with 14 TB of redundant storage, the OS actually uses less than 6 GB!
Yeah, thumb drives have really gotten enormous over the years.
My concern about the above would be, if one drive fails, you have to down the box, or at least slide the case out and open it, in order to change it. I would be slightly more inclined to do this with external drives.
Question: does the controller backing the four hot-swap bays support device carving? You can take one RAID array and expose two volumes to the OS, which appear as separate devices. Both 3ware and MegaRAID cards support this; I imagine Areca does too. One downside is that you can't replace the entire RAID5 on the fly, since it has your OS.
--keith
On 11/8/2013 12:57 PM, Lists wrote:
Saw a trick today, wondering if anybody else had done/tried this? Assume you have a 1U rackmount with 4 front-accessed drive bays, and you want all four bays for a 4-disk RAID5 storage.
The idea is to use an internal USB adapter and a couple of bigger USB thumb drives to install to, RAID 1 style, freeing up all your external drive bays. At first, I didn't think that a thumb drive would hold enough for the O/S, but in actual production use for a file server with 14 TB of redundant storage, the OS actually uses less than 6 GB!
USB thumb drives are really not that suitable for anything doing random writes, lots of small files, etc.
On 11/08/2013 02:06 PM, John R Pierce wrote:
On 11/8/2013 12:57 PM, Lists wrote:
Saw a trick today, wondering if anybody else had done/tried this? Assume you have a 1U rackmount with 4 front-accessed drive bays, and you want all four bays for a 4-disk RAID5 storage.
The idea is to use an internal USB adapter and a couple of bigger USB thumb drives to install to, RAID 1 style, freeing up all your external drive bays. At first, I didn't think that a thumb drive would hold enough for the O/S, but in actual production use for a file server with 14 TB of redundant storage, the OS actually uses less than 6 GB!
USB thumb drives are really not that suitable for anything doing random writes, lots of small files, etc.
Agreed! In the case of a file store, there isn't a whole lot going on with the O/S drive, just the drives that the O/S is hosting. The original post recommended that /var/log be run off the big partition being hosted (on spinning disks) to minimize writes to the flash drives.
On Nov 8, 2013, at 17:12 , Lists lists@benjamindsmith.com wrote:
On 11/08/2013 02:06 PM, John R Pierce wrote:
On 11/8/2013 12:57 PM, Lists wrote:
Saw a trick today, wondering if anybody else had done/tried this? Assume you have a 1U rackmount with 4 front-accessed drive bays, and you want all four bays for a 4-disk RAID5 storage.
The idea is to use an internal USB adapter and a couple of bigger USB thumb drives to install to, RAID 1 style, freeing up all your external drive bays. At first, I didn't think that a thumb drive would hold enough for the O/S, but in actual production use for a file server with 14 TB of redundant storage, the OS actually uses less than 6 GB!
USB thumb drives are really not that suitable for anything doing random writes, lots of small files, etc.
Agreed! In the case of a file store, there isn't a whole lot going on with the O/S drive, just the drives that the O/S is hosting. The original post recommended that /var/log be run off the big partition being hosted (on spinning disks) to minimize writes to the flash drives.
It’s worth noting that FreeNAS does more or less exactly this, using a USB drive with a more-or-less read-only OS image to serve some number of spinning or flash disks.
On 11/8/2013 2:40 PM, Jim Wise wrote:
It’s worth noting that FreeNAS does more or less exactly this, using a USB drive with a more-or-less read-only OS image to serve some number of spinning or flash disks.
yeah, but whats on that USB stick is mostly a single file thats loaded into a ramdrive, and a single XML file thats updated when you make configuration changes, which typically isn't very often...
On Nov 8, 2013, at 17:48 , John R Pierce pierce@hogranch.com wrote:
On 11/8/2013 2:40 PM, Jim Wise wrote:
It’s worth noting that FreeNAS does more or less exactly this, using a USB drive with a more-or-less read-only OS image to serve some number of spinning or flash disks.
yeah, but whats on that USB stick is mostly a single file thats loaded into a ramdrive, and a single XML file thats updated when you make configuration changes, which typically isn't very often...
Yeah, true.
How close is Centos (or the upstream) to being able to run with all but /var and /tmp readonly?
On Sat, Nov 9, 2013 at 4:31 AM, Jim Wise jwise@draga.com wrote:
How close is Centos (or the upstream) to being able to run with all but /var and /tmp readonly?
Don't know about CentOS. However there is Voyage Linux (derivative of Debian) that runs from an 'ro' filesystem + 'rw' files in ramfs.
On 11/9/2013 2:40 AM, Arun Khan wrote:
On Sat, Nov 9, 2013 at 4:31 AM, Jim Wisejwise@draga.com wrote:
How close is Centos (or the upstream) to being able to run with all but /var and /tmp readonly?
Don't know about CentOS. However there is Voyage Linux (derivative of Debian) that runs from an 'ro' filesystem + 'rw' files in ramfs.
you could use the centos liveCD as a basis for a ramdisk image ...
On Sat, Nov 9, 2013 at 4:13 PM, John R Pierce pierce@hogranch.com wrote:
On 11/9/2013 2:40 AM, Arun Khan wrote:
On Sat, Nov 9, 2013 at 4:31 AM, Jim Wisejwise@draga.com wrote:
How close is Centos (or the upstream) to being able to run with all but /var and /tmp readonly?
Don't know about CentOS. However there is Voyage Linux (derivative of Debian) that runs from an 'ro' filesystem + 'rw' files in ramfs.
you could use the centos liveCD as a basis for a ramdisk image ...
It is a thought.
However, for low storage (256MB CF), low mem (256MB), slower cpu (< 500 MHz) - VoyageLinux is a good fit. One can remount / 'rw' make the config changes, to make the changes persistent and then remount 'ro'.
-- Arun Khan
Please review http://plone.lucidsolutions.co.nz/linux/io/using-centos-5.2-stateless-linux- support-on-a-flash-based-root-filesystem
It's for CentOS 5.2 but the provided configuration settings apply to the entire 5.x series.
-----Ursprüngliche Nachricht----- Von: centos-bounces@centos.org [mailto:centos-bounces@centos.org] Im Auftrag von Jim Wise Gesendet: Samstag, 9. November 2013 00:02 An: CentOS mailing list Betreff: Re: [CentOS] Install to internal USB?
On Nov 8, 2013, at 17:48 , John R Pierce pierce@hogranch.com wrote:
On 11/8/2013 2:40 PM, Jim Wise wrote:
Its worth noting that FreeNAS does more or less exactly this, using a
USB drive with a more-or-less read-only OS image to serve some number of spinning or flash disks.
yeah, but whats on that USB stick is mostly a single file thats loaded into a ramdrive, and a single XML file thats updated when you make configuration changes, which typically isn't very often...
Yeah, true.
How close is Centos (or the upstream) to being able to run with all but /var and /tmp readonly?
On Sat, Nov 9, 2013 at 2:27 AM, Lists lists@benjamindsmith.com wrote:
Saw a trick today, wondering if anybody else had done/tried this? Assume you have a 1U rackmount with 4 front-accessed drive bays, and you want all four bays for a 4-disk RAID5 storage.
The idea is to use an internal USB adapter and a couple of bigger USB thumb drives to install to, RAID 1 style, freeing up all your external drive bays. At first, I didn't think that a thumb drive would hold enough for the O/S, but in actual production use for a file server with 14 TB of redundant storage, the OS actually uses less than 6 GB!
Here's the internal USB adapter specifically mentioned: http://www.amazon.com/gp/product/B007PODI1W
Some of the newer workstation/server boards have an internal USB (female) connector soldered on to the board; specifically meant for embedded OS. I have seen it on the Supermicro and Dell systems.
I'd be concerned about getting a higher quality drive than the $10 givaways at Staples; Anybody here ever tried this?
Make sure you do buy industrial quality USB pen drives. I use Apacer but there are others in the market.
I prefer to use SATA Disk on Modules (DoM). For basic server install a 2GB DoM is plenty.
In either case, do not put swap on the flash drive.
-- Arun Khan
On 11/8/2013 11:01 PM, Arun Khan wrote:
Some of the newer workstation/server boards have an internal USB (female) connector soldered on to the board; specifically meant for embedded OS. I have seen it on the Supermicro and Dell systems.
personally, I'd as soon use a CF or SD card for this, but ah well.
my home HP Microserver, running FreeNAS, has a sandisk USB stick plugged into its internal USB jack on the main board. has been working great for a year. occassionally I backup the configuration file so if the stick dies, in theory I make a new one and slap the XML file on it and reboot.
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Arun Khan -
Jim Wise -
John R Pierce -
Keith Keller -
Lists -
Thomas Göttgens