Hi, > Hi, > > > Hi, > > > > On Sat, 2023-04-22 at 09:20 +0800, Wang Yugui wrote: > > > Hi, > > > > > > Is there some work for gfs2 multiple device support? > > > > > Do you mean multiple devices generically, or specifically the md > > driver? > > > > > if multiple device support, > > > 1, No need of RAID 0/1/5/6 support. > > > ?? nvme SSD is fast enough for single thread write. > > I'm not sure I understand this. Multiple device support generally means > > at least one of the RAID modes. > > we can support linear mode (same as lvcreate --type linear) only firstly. > > > > 2, can we limit one journal into one device? > > The filesystem always assumes a single device with one or more > > journals. If multiple devices are used, that is done at the block > > layer, which is below the filesystem layer. > > > > > > > > 3, can we just write lock one device, so better write throughput? > > Do you have a specific application in mind? Or certain performance > > levels that you need to hit? The write performance will depend a lot on > > the I/O pattern, and the underlying device performance. We'll need a > > bit more detail to be more specific I'm afraid, > > gfs2 use 'SCSI PERSISTENT RESERVE' or similar method to lock block device > when multiple hosts access the gfs2 at the same time?
It seems that lock_dlm does NOT use 'SCSI PERSISTENT RESERVE' or similar method to lock block device. it lock in the unit of 'resource group'. Best Regards Wang Yugui (wangyu...@e16-tech.com) 2023/05/09 > if gfs2 use multiple device directly rather than through lvm, then we > can just lock one device rather than all device? > - journal lock one device only > - data write lock one device only. > > Now SSD/SAN is very fast and become cheaper, and we can use multiple > SSD/SAN for one bigger filesystem and bigger HPC cluster? > > Best Regards > Wang Yugui (wangyu...@e16-tech.com) > 2023/04/24
