From zbr@ioremap.net Fri Jan 16 18:10:50 2009 From: Evgeniy Polyakov Date: Wed, 14 Jan 2009 02:05:33 +0300 Subject: Staging: dst: kconfig and makefile changes. To: Greg KH Cc: linux-kernel@vger.kernel.org, dst@ioremap.net, Evgeniy Polaykov Message-ID: <1231887933-17843-8-git-send-email-zbr@ioremap.net> Signed-off-by: Evgeniy Polaykov Signed-off-by: Greg Kroah-Hartman --- drivers/staging/Kconfig | 2 + drivers/staging/Makefile | 1 drivers/staging/dst/Kconfig | 71 +++++++++++++++++++++++++++++++++++++++++++ drivers/staging/dst/Makefile | 3 + 4 files changed, 77 insertions(+) --- /dev/null +++ b/drivers/staging/dst/Kconfig @@ -0,0 +1,71 @@ +config DST + tristate "Distributed storage" + depends on NET && CRYPTO && SYSFS + select CONNECTOR + select LIBCRC32C + ---help--- + DST is a network block device storage, which can be used to organize + exported storages on the remote nodes into the local block device. + + DST is a network block device storage, which can be used to organize + exported storages on the remote nodes into the local block device. + + DST works on top of any network media and protocol, it is just a matter + of configuration utility to understand the correct addresses. The most + common example is TCP over IP allows to pass through firewalls and + created remote backup storage in the different datacenter. DST requires + single port to be enabled on the exporting node and outgoing connections + on the local node. + + DST works with in-kernel client and server, which improves the performance + eliminating unneded data copies and allows not to depend on the version + of the external IO components. It requires userspace configuration utility + though. + + DST uses transaction model, when each store has to be explicitly acked + from the remote node to be considered as successfully written. There + may be lots of in-flight transactions. When remote host does not ack + the transaction it will be resent predefined number of times with specified + timeouts between them. All those parameters are configurable. Transactions + are marked as failed after all resends completed unsuccessfully, having + long enough resend timeout and/or large number of resends allows not to + return error to the higher (FS usually) layer in case of short network + problems or remote node outages. In case of network RAID setup this means + that storage will not degrade until transactions are marked as failed, and + thus will not force checksum recalculation and data rebuild. In case of + connection failure DST will try to reconnect to the remote node automatically. + DST sends ping commands at idle time to detect if remote node is alive. + + Because of transactional model it is possible to use zero-copy sending + without worry of data corruption (which in turn could be detected by the + strong checksums though). + + DST may fully encrypt the data channel in case of untrusted channel and implement + strong checksum of the transferred data. It is possible to configure algorithms + and crypto keys, they should match on both sides of the network channel. + Crypto processing does not introduce noticeble performance overhead, since DST + uses configurable pool of threads to perform crypto processing. + + DST utilizes memory pool model of all its transaction allocations (it is the + only additional allocation on the client) and server allocations (bio pools, + while pages are allocated from the slab). + + At startup DST performs a simple negotiation with the export node to determine + access permissions and size of the exported storage. It can be extended if + new parameters should be autonegotiated. + + DST carries block IO flags in the protocol, which allows to transparently implement + barriers and sync/flush operations. Those flags are used in the export node where + IO against the local storage is performed, which means that sync write will be sync + on the remote node too, which in turn improves data integrity and improved resistance + to errors and data corruption during power outages or storage damages. + + Homepage: http://www.ioremap.net/projects/dst + Userspace configuration utility and the latest releases: http://www.ioremap.net/archive/dst/ + +config DST_DEBUG + bool "DST debug" + depends on DST + ---help--- + This option will turn HEAVY debugging of the DST. + Turn it on ONLY if you have to debug some really obscure problem. --- /dev/null +++ b/drivers/staging/dst/Makefile @@ -0,0 +1,3 @@ +obj-$(CONFIG_DST) += nst.o + +nst-y := dcore.o state.o export.o thread_pool.o crypto.o trans.o --- a/drivers/staging/Kconfig +++ b/drivers/staging/Kconfig @@ -93,5 +93,7 @@ source "drivers/staging/epl/Kconfig" source "drivers/staging/android/Kconfig" +source "drivers/staging/dst/Kconfig" + endif # !STAGING_EXCLUDE_BUILD endif # STAGING --- a/drivers/staging/Makefile +++ b/drivers/staging/Makefile @@ -29,3 +29,4 @@ obj-$(CONFIG_INPUT_MIMIO) += mimio/ obj-$(CONFIG_TRANZPORT) += frontier/ obj-$(CONFIG_EPL) += epl/ obj-$(CONFIG_ANDROID) += android/ +obj-$(CONFIG_DST) += dst/