Need help figuring out how to configure storage for my purposes and do RAMDISK boot
by MatCat from LinuxQuestions.org on (#4ZF2D)
Greetings, I recently purchased a DL380 G7 server to use in home primarily as a build server (mostly C++ projects), though I will also use it for other general purpose things like NAS and such. It's got dual Xeon x5660's 128GB of RAM, and 2 raid controllers, built in one has 8 drive bay on it, and 2nd raid controller also has an 8 drive bay, the internal raid controller has 512MB of cache, and the 2nd raid controller has 1GB of cache.
I am setting this up for as high performance as I can get, so one of the things I want to do is have a 16GB RAMDISK for OS and /var/logs, there will also be another 16GB RAMDISK used as scratch space for compiling and other intense but not larger then 16GB file R/W needs.
Now as far as actual storage goes I have 2x 128GB SSD, and 14x 500GB 7.2k HDD's. Because my 2x 8x drive bays are not on a single controller, I must split up into 2 HW raid arrays in total, my current train of thought on that is that each RAID will have 1 of the 128GB SSD's, which in linux could be software RAID 0, then each HW RAID would have 7x 500GB HDD's in RAID 5, where again they would be combined in software RAID 0 array for a 2x7x RAID 50. I AM NOT that worried or concerned about data safety, this is primarily a build server, if an SSD goes and wipes out the 16GB OS partition who cares, easy enough to fix, and infact I plan to have a handful of 16GB partitions on the RAID50 for OS backups and maybe OS swapping. That will give me up to 2 drive failures (1 in each array), and even then, anything of any real importance is GIT'd to multiple machines anyway, so performance over absolute data security. All storage will be btrfs.
Now on the SSDs I would love to use some of it for caching the RAID 50 (I almost don't even care about read cache, I don't think it will matter with this config, BUT WRITE matters, if its possible to have almost all write cache, and read through, that might be the ticket?), it will also hold 16GB partition for OS, this is where OS will be kept for persistence, and copied from into RAMDISK (and saved to). Any remaining space on the SSD can be used for scratch space.
For the RAID50 most of it will be a single volume, though I do want to maybe do 16 16GB partitions or something, these would act as A: backups for OS partition(s), as well as backup points for 16GHB RAMDISK scratch spaces, this would allow me to hotswap different working datasets to RAMDISK when I want to work on them.
Also the boot will be on either USB drive or SD card, as all it has to do is set up all the partititions, mount things, get the OS to RAMDISK and boot it.
Now to get to the meat of this very lengthy post, the first question: Does this seem like a good way to set this machine up to get the best performance and a tiny bit of data security (which is not that important)?
And secondly the even more loaded question, HOW DO I DO THIS! I know I need the initial boot partition (on USB or SD card), that will setup the mounts and the cache and copy the OS to RAMDISK and boot it, but I have no idea how to actually boot an OS in an interim state, also I have no idea how to properly setup the cache stuff and SW raid stuff (I sort of do but NOT for a boot config), also I have 0 experience with btrfs but I realize its probably far better suited for this and I know it has better methods for doing the partition copies then rsync.
I look forward to a response to this very lengthy post :).
I am setting this up for as high performance as I can get, so one of the things I want to do is have a 16GB RAMDISK for OS and /var/logs, there will also be another 16GB RAMDISK used as scratch space for compiling and other intense but not larger then 16GB file R/W needs.
Now as far as actual storage goes I have 2x 128GB SSD, and 14x 500GB 7.2k HDD's. Because my 2x 8x drive bays are not on a single controller, I must split up into 2 HW raid arrays in total, my current train of thought on that is that each RAID will have 1 of the 128GB SSD's, which in linux could be software RAID 0, then each HW RAID would have 7x 500GB HDD's in RAID 5, where again they would be combined in software RAID 0 array for a 2x7x RAID 50. I AM NOT that worried or concerned about data safety, this is primarily a build server, if an SSD goes and wipes out the 16GB OS partition who cares, easy enough to fix, and infact I plan to have a handful of 16GB partitions on the RAID50 for OS backups and maybe OS swapping. That will give me up to 2 drive failures (1 in each array), and even then, anything of any real importance is GIT'd to multiple machines anyway, so performance over absolute data security. All storage will be btrfs.
Now on the SSDs I would love to use some of it for caching the RAID 50 (I almost don't even care about read cache, I don't think it will matter with this config, BUT WRITE matters, if its possible to have almost all write cache, and read through, that might be the ticket?), it will also hold 16GB partition for OS, this is where OS will be kept for persistence, and copied from into RAMDISK (and saved to). Any remaining space on the SSD can be used for scratch space.
For the RAID50 most of it will be a single volume, though I do want to maybe do 16 16GB partitions or something, these would act as A: backups for OS partition(s), as well as backup points for 16GHB RAMDISK scratch spaces, this would allow me to hotswap different working datasets to RAMDISK when I want to work on them.
Also the boot will be on either USB drive or SD card, as all it has to do is set up all the partititions, mount things, get the OS to RAMDISK and boot it.
Now to get to the meat of this very lengthy post, the first question: Does this seem like a good way to set this machine up to get the best performance and a tiny bit of data security (which is not that important)?
And secondly the even more loaded question, HOW DO I DO THIS! I know I need the initial boot partition (on USB or SD card), that will setup the mounts and the cache and copy the OS to RAMDISK and boot it, but I have no idea how to actually boot an OS in an interim state, also I have no idea how to properly setup the cache stuff and SW raid stuff (I sort of do but NOT for a boot config), also I have 0 experience with btrfs but I realize its probably far better suited for this and I know it has better methods for doing the partition copies then rsync.
I look forward to a response to this very lengthy post :).